The long cart path down the far edge of the property dog legged by a huge pile of warped and torn sheets of thick oriented strand board (OSB) that the oven foundation builders had used to bring in thousands of pounds of stone and some pretty heavy machinery across a beautifully manicured lawn.

We delivered all of our oven materials, the copper dome, grog, dome elements, etc., with four or five cart trips and covered each pile of materials with new tarps in case it rained.

We had seen photos of the completed oven base before we arrived, so we knew what to expect and that it was beautiful, but we were still moved by how well placed and how beautiful the foundation was and is.

A few months ago, Albie and a friend had spent a couple hours online looking at literally hundreds of oven installation photos, many with stone foundations, and we were surprised by how unbalanced most of them looked, with huge outsized wood boxes and poor relationship to the oven mass itself. We were, at that moment, designing a stone foundation for Albie’s friend’s oven and we wanted it to be both beautiful and functional and balanced for her to work with and look at.

The defining element for her foundation were two gorgeous limestone footing columns that we dug out of the ground. Each column was part of her old barn foundation and each column was buried three feet in the ground tightly packed with smaller stones around it.

Over the Fourth of July we finally placed a heavy granite lintel from Maine Pownal granite which Albie had found and bought while working on the Pownal, Maine Thurrell project and had brought to New Jersey in an earlier trip.

Trimmed with hammer and chisels and rolled on planks and then lifted into place with a chain fall, it makes a wonderful addition to the evolving stone veneer of hand cut limestone salvaged from the old barn foundation on her property.

An oven designed to last for a generation or more should be beautiful as well as functional and the foundation at the Harvard home was both. We were contacted several months ago by the landscape designer and architect Roger Washburn who told us that he had a client in Harvard, Massachusetts who was interested in one of our copper topped ovens. We provided Roger with the diameter, height and weight of our turnkey 83 copper oven and Roger took the project under his wing in earnest. Roger took time and care, consulting regularly with his clients and presented them with a concept that placed the oven at the 9:00 o’clock perimeter position on a round masonry circular patio placed just beyond the lower level exit from the home.

The stone foundation for the oven related to other stone walls and steps around and directly serving the home. The house itself, built thirty or more years ago by the family (and constantly being refined and improved upon) is set on a slope.

The walk from the driveway to the main deck that wraps the side of the house at ground level and becomes an upper level behind the house, is accessed by a series of long steps made from large thick slabs of bluestone. The “riser” or face of each thick bluestone slab is hand chiseled with large elegant flakes defining each slab face. Roger picked up this motif of the thick bluestone slabs in his oven design and capped the foundation with two sawed and shaped six inch thick bluestone slabs, tightly joined at the center.

The chief cook in the family requested generous working surfaces to the left and right sides of her oven door. The aspiring baker gave his blessing as well to the design and her priorities. Roger’s design, looking down from the upper level deck or the trees, created an oven foundation cap that reminds me of an Omega symbol with a horseshoe circle rear curve and balanced legs off to each side. The perfectly matched pair of sawed, leveled and chisel faced cap stones gave us a stunning base for our oven assembly work.

Beneath the pair of cap stones, a mason had spent a day cutting and chiseling a curved Corinthian granite lintel to cap the modest wood box below the oven opening. Roger’s design, we hope, will inspire other folks to consider something similar when they wish to do a “round” base for a Le Panyol oven at a perimeter location on a circular or non-circular masonry patio.

June rains stopped once we arrived and our carefully tarped piles received little or no rain and we worked in sunshine throughout the project. We positioned the oven on the base with a seven-inch equal border from side to side and at the rear. The side extensions and the front apron were deeper. Pencil marks on the stone slabs kept our layout honest. We usually set our turnkey oven pans on 3/8 inch thick small four inch square stone tile shims to allow for water evaporation to occur beneath the pan.

Our client had twelve inch square remnant tiles in hand. We tried unsuccessfully to cut 4 inch by 4 inch tiles from the larger tile with our diamond grinder, but the segmented teeth vibrated the slate and caused it to delaminate every time. After destroying two foot square tiles, Ryan and I drove to a nearby Home Depot and picked up some 6 inch square indoor/outdoor ceramic tiles which we laid out in two circles plus a center shim to support the oven in its pan. We set the metal pan in place but it rocked on the center shim, so we removed it and trusted the two circles of tiles to hold the oven adequately as the pan is fully reinforced with six five inch high reinforcing “ribs”. We dry laid the numbered pre-cut pieces of three inch thick calcium aluminate Skamol rigid insulation board and then poured in fired and ground up Terre Blanche (white earth) grog to blue tape lines we had preset around the pan. Scott and Brock had sent us a measured and stepped screed board from Maine to level out the grog. Using weighted rubber mallets and short 2 inch by 8 inch blocks of wood, we settled all the grog with lots of mallet-on-block pounding, and moved the blocks bit by bit across the entire surface of the grog layer until the grog was very well compacted. The balance of the grog we saved to feather under each floor tile as we laid and leveled each row from the center tile out to each side and from front to rear. Near the rear, out beyond the dome perimeter, we added a bit of masonry scraps to the grog to get the grog height at the rear edge up to the level of the whole.

The oven dome went together smoothly. We located the lintel element and smoke throat elements centered on the stone cap center line and spaced them back about 1/2 inch at the smoke throat element corners to leave plenty of room for fitting the copper dome and did a trial fit (one of about three or four fittings) of the copper dome and then returned it to skids under the deck. With the position of the lintel and smoke throat elements and keystone clear, we marked them with pencil and then bonded them to the floor and one another with clear high temp silicone caulking and then clamped a two by three inch by eighteen inch straight edge to the front three elements of the smoke throat assembly to hold it together and tightly fitted while the caulk set up.

By keeping the eighteen inch long piece of two by three stud below the top edge of the smoke throat elements we were able to work on the oven and the smoke throat adaptor without removing the straight edge until the three pieces had fully cured. With the keystone set and the lintel and smoke throat elements in place, we laid in the first two straight voissoirs, one on either side of the lintel element and tipped slightly forward to make a tighter fit with the keystone. The bottom edges of the voissoir elements were rounded slightly to allow for this slight tipping and we used wooden clothes pin halves as perfect little temporary wedges to hold the voissoirs at their tipped forward position. We marched around the oven fitting all the voissoirs perfectly until the last tapered voissoir which was just a bit too tight, but with a couple taps of the rubber mallet on the adjoining voissoirs, room was created for the last voissoir dome element to slip in. Ryan also used a technique to shift voissoirs around a bit that I had never previously used which was to slip his trowel under the base of the tipped voissoir and to gently lift and pull the base out a bit and this was very effective along with the interior and exterior mallet tapping for a little fine tuning of the voissoir layout so that the base “circle” was smooth and the fit at the keystone all even and at the same level at the ceiling of the dome.

We wrapped the base with two tight strands of tie wire anchored to long tapcon screws drilled into the base sides of the lintel element and then packed any open top joints with single folded sheets of paper towels, tucked into place by folding each small piece in half over the side of the trowel blade and using the trowel to slip it into the gap. The half voissoirs over the lintel we trimmed back at the base about 1 ½ inches and drilled and screwed into position four short perforated galvanized angle iron sections, one behind each half voissoir to avoid any shifting of the half voissoirs during the life and use of the oven. We used pan head short tapcon screws to secure the angle iron strips and to keep the screw heads as close to flush with the strips as possible. With the half voissoirs and the galvanized angle strips in place, we then mounted the stainless steel smoke throat adaptor on two layers of high temp flat braid fiberglass ribbon gasket with a bed of high temp silicone between each layer and tapcon screwed the adaptor into place with the four holes already drilled in the corners of the adaptor and us drilling corresponding holes in the smoke throat and lintel elements. We use hex head tapcon screws for this final mounting.

We sprayed down the dome several times with a hose to get the highly absorbent Terre Blanche wet enough to receive the refractory mortar skin coating. We poured mortar into the open top gaps first and then pargetted the entire dome with Ryan passing Albie cut off half bottles of pretty soupy mortar which Albie applied with a rubber gloved hand and a small trowel.

We also filled the gaps beneath the base elements, removing the wooden clothes pin shims as we went around the base. We let the mortar skin set and dry for several hours and then applied four (inch thick) fitted layers of a very high quality high temp ceramic bio digestible (lung friendly) blanket insulation. The insulation comes in long rolls so sections are draped across the dome and then the pieces are folded over tightly with overlapping sections cut out and the new shapes joined at their edges. In subsequent layers, we avoided putting a seam over a seam. We drilled and screwed in three 2 ½ inch by ¼ inch tapcon screws on each side of the lintel element and used these screw heads as anchor points to wrap tie wire tightly in hoops at different angles over the blanket insulation on both the final layer and some intermediate layers.

For the final copper dome mounting, we used three people instead of just two and everything slipped nicely into place. Even as oven and masonry heater professionals, both Ryan and Albie failed to realize that the new series stainless steel rounded cap mounting machine bolts were designed to be screwed in with a hand held wrench versus a torque head driver drill, Albie managed to snap off a bolt in the stainless base pan threaded hole before he realized the error of his vision and method.

Scott and Brock had provided Albie with a little piece of cardboard with a green torque head bit and a larger black head bit and a correct Allen wrench with little notes and drawings to explain which was used where, but old habits are blinding and neither of us got the message straight. Luckily for us, our client had a machinist background, among other things, and a fully equipped shop and he quickly produced a small center punch and and tap and die set to help us solve our problem. Albie started with a very small bit and then worked his way through three or more subsequent larger sizes. Out came a metric drill bit designer for the quarter inch tapping tool and he finished the hole with that and then cleanly re-threaded the hole. As soon as Albie got home he humbly sent down the new rounded cap machine bolt and a couple of spares and the oven dome was complete.

The stainless smoke stack and the cap and collar mounted smoothly and we shimmed the base connection firmly in place and plumb with strips of the high temp fiberglass blanket. In little trees to the left and right of the oven, tiny nearly invisible spot lights had been mounted and wired in place to illuminate the oven working surfaces after dark.

With perfect hosts, gourmet snacks and meals, including fresh Snake River Alaskan salmon picked up after an email sent to customers of a local Costco food store, along with this remarkable outdoor setting and gorgeous base, we were delighted with our roughly twenty hours (times two men) of effort on site to create an oven to use and to behold. We look forward now to cooking and baking feedback from our new found Harvard, Massachusetts friends.

Albie started thinking about using large clay flue tiles as the outer skin of a lower cost masonry heater about l0-l5 years ago. It all began when he saw a line of twenty or so 500 pound round two foot tall, thirty six inch inside diameter and 3″ thick tile, laying in a deep snow bank beside the road in Madison, Maine where a new Junior High School was being built.

The tiles were to become the chimney flue liner for the big boiler that would heat the large new building. He did not know at the time that such large and heavy clay tile liners were being made, but he liked them. He liked the color, the shape, the thickness and the height. You can roll a two foot by three foot tile up a ramp and through a door. With some simple lifting equipment you can even set one tile on top of another and have a stack four feet or six feet tall.

He began designing a masonry cooker/heater with Hans Nicholaisen. Master welder and designer in his own right, of Waldoboro, Maine with whom he had done several previous projects. When they were done they had a round clay tile masonry cooker/heater with a common brick on edge liner mortared in clay and a 22.5″ by 22.5″ square (o.d.) firebrick firebox centered in the tile liner.

Covering the top of the tile, Nick fabricated a lipped heavy steel top with a round cast iron loading plate in the center. Little covers near the edges adjusted draft controls that fed into steel channels under the top and turned ninety degrees down into the two front corners of the firebox. Left to right across the firebox and down the sides into the heat exchange channels, Nick designed and fabricated a baffle assembly that rested on top of the two sides and rear of the firebrick firebox.

In the rear of the baffle, a pivoting plate with a handle protruding through the cook top allowed a quick start kindle position for the gases to go directly up from the firebox, through the kindle damper opening into the round collar and stove pipe on the top rear of the cook top. With the kindle damper closed, the flame and smoke came up to hit the cook plate/loading lid then went down the front three channels, under the baffle and then up the back channels and out the chimney flue. Air coming through the rather long horizontal draft tubes was pre-heated before entering the firebox.

We took this original masonry heater design to the Common Ground Fair for a couple of years. It developed a vertical hairline crack in the tile which did not affect its performance. Although it was possible, we did not add to this unit a domestic hot water jacket. We eventually sold and installed the unit in a modest owner built passive solar home in Gouldsboro, Maine where it worked very well as a primary masonry cooking and heating source in the home. It was the beginning of our work with clay tile lining and led to new interesting projects down the road.

Inspiration for innovative masonry design can happen just about anywhere… in the heart of a home, or even a portable yurt.

During the summer and fall of 08, we were joined by a fine young mason from Pennsylvania and Colorado named Matt Helike. After a month or two of Matt tenting in our woods, we reacquired a twenty-foot portable yurt about thirty years old. We picked it up with our empty flat bed trailer after Matt, Arthur and Albie completed a huge six sided stone masonry heater with soapstone heated bench and caps in the Adirondacks last summer.

The yurt had started its career here when Peter and Trish Glasson were part of a metal stove building team that had their workshop in our garage building the Sunshine Stove, many of which are still in use today. Peter and Trish took the yurt with them when they moved away but it came back for a second stay when John Fisher, now a well known masonry heater and oven builder living in Sweden, apprenticed with us for a bit for more than a year and set the yurt up on stilts in a little hollow wet run in the woods.

Matt chose a new spot further into the woods in a little flat spot surrounded by hardwood trees not yet ready to blow down on something. He dug deep holes and gave it a beautiful foundation of pressure treated posts and joists to support the deck panels. He also added a nice hatch cover insulated root cellar accessible from inside the yurt, but his even more ambitious accomplishment was a large masonry footing and foundation dead center below the yurt on which Matt designed and built a second generation three foot by two foot clay tile masonry cooker/heater. He used the last clay tile of the three I bought many years ago and also used recycled brick and firebrick we had on hand. He wanted to avoid buying a fancy metal top and baffles so he spent hour after hour scratching his head and designing a highly efficient and attractive wood heating system from materials we had on hand.

Matt did all of the work on his own with only very fleeting visits from Albie to check on his progress. The design and construction challenge of the masonry heater/cooker within the yurt was a big one and the more Matt did on his own, the more he learned. He decided that he wanted to build his cooker/heater three feet tall so he laid up several courses of brick in a matching circle as a base to set the tile on. He then decided to bring in combustion air through the base brick course and inside the liner brick wall before introducing it to the upper firebox corners from within the unit. He made all of these air channels out of carefully cut masonry. He walked many cuts over to our powered red shed and the big wet diamond saw and also worked some of his project from the site with our Honda generator.

Matt decided to cast the top in a couple of large slabs from castable refractory rather than using metal and he installed a modest cast iron rectangular plate with a round 7-8 inch lid in it as his cook plate and loading port. With Chris helping in our masonry shop, they designed and fabricated a kindle damper with the handle protruding through the plate. And in a final community push, Scott, Chris and Matt all installed a stove pipe which traveled through one panel of the faceted ceiling skylight, (plexiglass replaced with metal) and transitioned through a roof mount factory chimney section with a smaller factory chimney above the roof.

Matt got engaged just before he joined us and left his fiance working for the Forestry Service in Colorado while he travelled to Maine. With the modern blessing of cell phones and unlimited calling plans Matt kept in constant touch but his heart kept calling him back to his love far away. He stayed as long as he could with us and worked on a few good projects and stayed one extra night, working well into the wee hours to finish his cooker/heater and then decided to give it its maiden voyage burn and sleep in the yurt for the first time with real cozy masonry wood stove heat. He left with pride in his heart and a gleam in his eyes.

The yurt is up with the round cooker/heater gracing the center ready for the next guests to arrive.

For the past ten years, we have been importing Le Panyol wood fired ovens from France. The wood fired ovens of France have a design that goes back to Roman times. Wood was placed directly on the hearth under the flue to start the fire and as the fire engaged, the fuel pile was pushed as a crib to the rear. This is the same firing process we use today. This gas flame burning at the rear travels to the ceiling and heats the entire oven core. Ashes from non-treated wood are not toxic so a small amount of ashes left on the floor of the oven, even after a burn, presents no health hazard to the user.

Some wood fired ovens, such as the Poilane ovens in Paris or our model 250, are fired from below the hearth floor with the oven recharged, whenever necessary, by stoking the fire below and directing flames into the oven through a cast iron elbow called a gueullard. The gueullard can be rotated left or right as it swivels in a cast iron ring set into the hearth so it is easy to get flame and heat everywhere in the oven. Once the oven is recharged, the gueullard can be removed and set aside and a cover, with or without a water pan, is set on the round hole just inside the door of the oven.

Coal is much denser than wood and has a much shorter flame path. Traditionally, one could not light coal on the floor of the oven without a grate. The grate would have to be scraped across the floor or located in the rear with difficulty in filling the grate from the door. In the first half of the twentieth century there were a large number of commercial coal fired ovens in the States, mostly in urban areas. Coal was easier to store and had a longer burn but a shorter flame. Such ovens were designed with a firebox below and to one side of the oven door. The oven floor and oven cavity were typically square or rectangular in shape. Very heavy cast iron doors would cover the firebox opening. Inside the firebox there would be a heavy “shaker” grate. On the hearth floor itself there might be a fixed grate that the very hot exhaust gases could pass through on their way to an exit at one or both rear corners of the oven. Such ovens had relatively low ceilings, often only slightly arched and sometimes flat with heavy firebrick tiles hung on steel channels from above.

The very famous Italian pizza ovens of New Haven are these heavy under fired coal burning ovens. The exhaust gases hang at the ceiling level and stay in a layer above the food, but no smoke and very little ash gets into the food. I visited a patented design coal fired commercial bake oven in Colchester, CT. many years ago that had two side by side fireboxes underneath the oven floor and then the exhaust gases were carried in a manifold (of as many as six) 6″ diameter cast iron pipes set in the mass on top of the oven arch. These all come together over the front of the oven and exit the chimney. This oven could run constantly with heat all around the oven adjusted with additional fuel and draft controls. No flame or fuel dust ever entered the oven.

The arched dome ovens by Le Panyol have no design relationship to any of these traditional commercial coal fired ovens and there is no easy or safe way that we know of that our Le Panyol models can be reasonably converted to coal. We also believe in the efficiency and durability of the Terra Blanche material that makes up the Le Panyol oven core. The thermal properties, conductive surface and the unique dome shape design ensures even heat distribution resulting in unequaled culinary versatility.

Their timber framed home earned a timber framed two story ell addition with office, sitting room, and another upstairs bedroom as their family grew. Two hundred feet away Bob built a timber framed shop and partnered with another man, designing, crafting and erecting sturdy timber frame homes and buildings, most within fifty miles of their base. Bob played a role in founding the Timber Framers Guild of America as a way to share information, to keep workmanship quality high, and to create a path for young people to enter the tradition. Albie at the same time was writing and publishing the free Masonry Stove Guild Newsletter in a similar effort to start a fledgling masonry heater working group in North America. He was key in forming, with a handful of other folks, The Masonry Heater Association of North America which is still going strong today.

At some point, Bob doubled the size of his shop with a two story timber frame addition and built a block chimney at its center to receive a wood burning stove. When Albie got called into the picture, Bob, Lynn and their young married daughter Hanna and her husband Chris, were all living in the Cape and ell. All three of the Thurrells were teaching at the local Waldorf school in Freeport which is one of the few Waldorf schools around with grades 1-12. Bob was teaching sciences and wood working with his Geochemistry and timber framing background. Lynn was a first class teacher which means she has taken two classes (of the same students) from 1st Grade through 8th – teaching all subjects except French and German. She has now taken up another class and is in 6th. Hanna was teaching one of the early grades.

Bob and Lynn had waited thirty years to call us, having known about our masonry heater work all the while. Now they were in the process of selling their home and a good chunk of the property to Chris and Hanna and had the intention of downsizing a bit and taking over the two story, soon to be improved and better insulated, shop addition, leaving room and tools still in the original shop to carry on the woodworking tradition which clearly feeds Bob’s soul. The leading edge of the shop addition was less than ten feet from the two hundred foot zoned set back for a new dwelling so even though the building was already legitimate and standing, there was still a need to seek a variance to be able to convert the building into a dwelling. (As I drove home this morning from an early morning appointment, there was story from Haiti of the families who had been inhabiting the median strip of a six lane highway for the past year waiting for some kind of government relief. Now about one thousand small rough plywood houses with a concrete floor and a tin roof were being provided and families of six were tearing apart their tiny North Lane to South Lane abutting median strip shacks to get ready for their move).

The variance came through and we targeted a late fall date to start their heater. We wanted to build connecting to the original block chimney, and the best orientation to the living space and new planned layout was a corner heater backed up to the chimney and facing diagonally into a longish and narrow living area. A normal corner heater has straight line facets to form a pentagonal shape. Lynn, however, wanted a rounded feminine form and a stucco finish along with a heated bench capped with local naturally cleft Pownal granite. Albie drew up a conceptual sketch and once this was approved, drew up a scale foot print sketch that all agreed would work. He then made a trip to the job site and drew the plan out full scale on the floor, showing both the heater and bench lines as well as the set back lines 2″ further out for the framing beneath the floor. While Albie worked on a stone heater project in Wilton, Maine, Bob cut and reframed the floor and with a little help from the carpentry crew, formed and poured a large footing in the crawl space basement.

Bob hooked up a wood stove to the back side of the chimney and several people, especially Stefan Apse, carried in all the blocks, mortar, concrete pre-mix, bricks, firebricks and flue tiles where they could be dry and warm and readily accessible. Stefan and Albie built the foundation on the footing that Bob had prepared and did numerous forty five degree angle cuts on 4″ thick concrete block solids double stacked, to create the pentagonal corners and support needed for the capping pour to follow. With so many wet saw cuts to make, Albie and Stefan assembled a plastic lined box below the saw and stapled plastic sheets to the wall and let them drape into the top of the box to catch the spray generated by the saw.

Bob came in every morning before dawn to pull wires, putter and start the wood stove and stayed until just before his first school class and often returned late in the afternoon to join us once again. As we neared the floor level with the foundation block, we formed up for the large curved bench pour which would cantilever out over our angled block work. We took a long 10″ tall strip of l/4″ plywood and bent it into a curve. Bob cut a series of backing braces and blocks so that we could adjust the curve and once we had it where we wanted it, we screwed the backing braces to the floor and the plywood to the braces. It was easy then to trace the inside edge of the curve and for Bob to then cut to the line with a reciprocating saw. With the curve in the floor cut out we still had the requisite 2″ clearance from any framing members even at the closest points of the curve. On the floor joists below the floor, we cut out and fitted tightly to the block work and screwed to the underside of the floor joists one or more flat 2″ by 4″ or 8″ or 10″ planks to give us a base to drop the curved plywood down on to and to give us a floor for our cantilevered pour. Any joint was covered with blue masking tape or duct tape and slight height differences were adjusted with nicely fitted pieces of cedar shingles. We dropped the curved plywood down into the hole and secured it on the back side of the curve with small blocks of wood screwed to the flat members and we shimmed out the top just a little bit with a series of cedar shingles along the length of the curve and screwed through the plywood and shingles into the floor decking to give us a stable curved concrete form which could be easily removed after the pour. One cedar shim shingle behind any pouring form board will, when removed, always give just enough room to release the form board. Once the flat lower decking of the pour is removed, it is an easy matter to drop the forming side boards into the basement crawl space. We calculated a centered ash dump and made up a plug for the ash dump out of two pieces of blue styrofoam, each measuring 9″ wide and 12″ tall. We put cedar shingle shims between the two pieces of styrofoam and taped the whole assembly together and inserted it slightly into the hole we had cut in the two layers of concrete board which would be the base support for the pour. I usually duct tape tabs around the base of the plugand sometimes drill in long screws to brace the plug during the pour. Our photos may also show a fairly heavy angle iron across the void to support the center of the pour under the double layers of concrete board.

We cut a quantity of 1/2″ rebar and tied it together at every joint with speed ties and set it up on concrete shims within the oiled form that we had created. All the corners and seams were sealed with tape so that the pour would not leak. Albie marked a level line on the form 3″ below the floor decking to leave room for the Skamol insulation board which we put on top of the concrete pour. Bob intended to add a 3/4″ ash floor on top of the original decking so we knew that 3″ from the current floor gave us plenty of room for our insulation board plus a mortar joint. Albie ran out of time to start the pour after the rebar was finished and was concerned that the pour would have been ideal to do before the long weekend ahead. Adrian, the builder, suddenly stepped up and volunteered to loan his crew and himself to work with Stefan to mix and pour the concrete that evening before the weekend. Albie knew that this job was special, special in many ways, one of which was the remarkable co-operation and generosity of all the contractors and helpers as they assisted one another. I think that Bob and Lynn, both remarkable and generous people, inspired this spirit on their site and it was always a pleasure to be there every day. After the foundation of the masonry heater was completed, we were joined by a third team member, our mason friend Ryan Neidhold of Vermont who has worked on many heater and oven projects in the past couple of years with Albie.

On top of the foundation cap slab we laid 3″ of calcium silicate (Skamol) board, to which we stapled aluminum foil, so that it would not so readily absorb the moisture in any mortar applied to it. With a base course of common bricks, we filled in the center of our heater base and also laid up six courses of veneer brick. To create the desired bow curve around the front of the heater, we made several skew cuts on the ends of the common brick to maintain tight joints. We also located and created openings for, and mounted, several small airtight clean out doors, giving access to each of the three downdraft channels as well as all parts of the long curved bench. We shimmed out each of the five or six clean out doors and ash box door approximately 3/8″ to allow for the stucco coat which would follow to come flush to the back edge of the soot door frames. These shims we cut from strips of 3/8″ wood on the job site. After a day, the doors and wire ties set up firmly enough and the shims can be easily removed. While they are setting up we typically get them leveled and plumb and then hold them into position with a short stack of dry firebrick in front of each door.

The core, set at a 45 degree angle to the brick veneer of the heater, laid up easily, leaving room for three identical downdraft heat exchange channels on the two sides and rear of the core. As we neared the top of the core and channels, we cut a by-pass channel hole into the back side of the block and tile lined chimney, almost opposite the spot on the far face where the wood stove was plugged in. Once the hole for the by-pass was completed, we plugged it temporarily with a panel of 3” Skamol board with a layer of ¼” mineral wool around it and this worked fine to create a smoke proof and safe environment while we moved towards the actual installation of the by pass channel when the veneer wall reached that point.

We also had to cut, much lower down, on the side of the chimney, a similar hole for a second by-pass channel to be located where the bench entered the chimney. When a chimney is already built, we do not try to cut a guillotine damper into a tile lined brick or block chimney and we prefer not to use a chimney top damper as some masons do. Instead, we do a spring loaded base exit by-pass channel. By adding large washers and a short stiff spring section, we can allow the user to have a range of settings from fully open to fully closed. A base exit damper also should not be a guillotine damper because it is likely to stick out into the room and have somebody trip over it.

From the right rear down draft channel to the right side down draft channel, and picking up the gases from the left side down draft channel through the underfloor common horizontal channel, all the exhaust gases exited the heater at the far right side of the long curved bench. The first flue tile exiting from the heater is laid on edge and gasketed against the down draft channel base opening. Turning the corner at the right side of the bench, we turn the tiles flat and cut them with skewed ends to follow a faceted shape along the curve of the bench. The first flat tile is fitted to the upper two thirds of the first exiting tile on edge. Square holes opposite the soot doors are also cut into the tiles. Additional support under the flat tiles which come to just below the top of the 6th common brick course, is provided with solid concrete blocks. Bridging the ash chamber channel, we covered the flue tile in that section with a stainless steel sleeve. All the tiles were dry fitted and laid in place and at the far left corner, we again turned the tiles on edge to make the entry into the chimney. Once everything was dry fitted, we started at both ends and worked towards the middle. Each tile is set on a sheet of ¼” mineral wool with wool on either side of the tile as well. Each tile is bonded to the next with refractory mortar and when the joints are sponged clean inside and out, we add a flat braid saddle gasket, secured with high temp silicone clear caulking, over the joints and then add a final layer of wool on top of each tile. The last tile we installed was to the right of the stainless steel sleeved tile and this was double buttered and dropped into place with strings wrapped around its belly. Surplus mortar is sponged off on the inside through the clean out ports. The tile opposite the left side downdraft channel had to have a hole cut in its far side, towards the core, as well as a matching hole on the veneer side to give access to that channel. We put a gasketed plug in the hole towards the downdraft channel so that all the draft would flow to the far right corner of the heater. The plug would give the Thurrells access to this channel once a year when they do their annual cleaning with a shop vac.

When back in Norridgewock over a weekend, Albie went out to our stone yard and loaded up a few hundred pounds of 1 – 2″ thick granite and soapstone cut off pieces and brought them back and inside to the job in Pownal. With the curved bench and the curved face and side, we wanted a way to fill the voids without slush filling wet mortar tightly against the mineral wool gasketing. In a standard heater, we often have a small gap between the gasket and the back of the veneer wall which we carefully fill with mortar without trying to push it in or pack it down. In the bigger voids in the curved bench and again in the voids on the side and front walls, we laid in 1 – 2″ thick pieces of stone gently against the mineral wool gasket and then slush filled the little remaining gap between the stone and the veneer wall. This allowed us to retain the free floating “Doll inside a doll inside a doll” principle in our construction and dramatically reduces the risk of cracking in the veneer from thermal stresses.

Knowing that the finished brick work was going to be covered by up to 3/8″ of stucco, we purposely did not obsess about plumb lines or perfect curves in the layout of the brick, knowing that everything would be smoothed over and organically finished with the stucco. Had the plan been to leave the brick work exposed, we would have had plumb lines at several points on the curve and would also have likely used a curved convex plywood template to check each course. Instead we used our eyes and our four foot levels to keep the project from wandering much out of plumb or level. To follow the gentle arch of the Future Series Loading Door we faced the challenge of filling the space behind the curved brick work back to the flat facet of the core and also creating both a lateral curve and a curve of the edge of the arch itself. We noted that by laying the bricks on their edge with one end towards the core face and the other towards the curve of the veneer we could custom cut both ends of every brick to the approximate desired shape. We did not, however, have a radical enough arch to allow us to cut wedge shapes with each brick as one might do with a “taller” brick arch layout.

When an arch heats up and expands, the normal wedge shape of the bricks keep the bricks securely in position, even if a hairline crack develops, but with our required layout we had no such wedge form protection. After some serious head scratching, we came up with two ideas which seemed to work. First, we cut some scrap metal diamond lathe (for wall stucco applications) and cut a piece of it to “spring” under the arch layout of the brick and create a web structure under the brick arch which would eventually be covered with stucco.  The metal lathe would also give the stucco something good to grip to under the arch. Secondly, we wove through the wire mesh at every joint a double tie wire loop and then laid the ends of each loop down flat on top of the bricks on either side of each vertical joint. This in effect “cinched” the bricks into position and to the wire mesh support so that everything in the arch would be locked together and mutually supporting. The front of each arch brick was gently curved on a radius to soften the feeling of the opening. The arch over the oven door we even made a little proud knowing that when stuccoed it would have a slightly raised “eyebrow” quality to it as another subtle accent. Scott Barden did similar curved arches with factory radius molded bricks on an earlier heater for a family in South Freeport which Albie liked very much and tried to emulate in this project.

For years, driving through this part of Maine, Albie had notice the uniqueness of Pownal’s granite, seeing many old posts and mile markers at numerous intersections in the area. The tooling on the granite sentinels indicated that the stone split large flakes when dressed by the early hand tool carrying masons. This grain structure of the stone helped to create a beautiful sculpted, versus a machined, look to the finished stone. As luck would have it, Bob and Lynn were already familiar with and very fond of the unique Pownal granite. One day Bob took Albie down the road in his old flatbed pick up truck to visit a one man active quarry less than five miles away. The quarry covered two or three acres. It was not deep or water filled. You could quickly see that the Pownal granite presented itself in layers, some as thin as 2 or 3″ and some as thick as a foot or more. The owner could quarry the stone with a back hole and bucket loader by prying loose and picking up large sheets of the stone and then could work it to any standard or custom size with cut off saws, drills and feather and wedges.  We were looking for a large piece about 3″ thick from which to make our bench stones and leaning vertically against a wall we found a piece about five feet by seven feet that seemed perfect for our needs. Then we bought two or three smaller 3″ pieces to supplement the big one should we need more material.  We cut the modest stone for the oven shelf first from one of the smaller pieces to see how it cut and chiseled as a kind of trial run for the bigger stone.

As we neared the top of the heater in our brick work, Ryan took on the task of templating the entire bench first with cardboard and then armed with these carefully fitted pieces and a gas powered cut off diamond saw, went outside to see how many of the bench pieces he could cut out of the one large naturally cleft stone.  Cardboard laid flat on the ground can fit piece to piece quite perfectly, but a naturally cleft stone, once cut, when laid on the level support walls below it, and intended to be level above, does not behave nearly so tamely.

Ryan cut all the pieces beautifully with the saw and then Ryan and Albie did much of the curved stone face live edge chiseling. When we went to lay these naturally cleft stones, we found it very challenging to achieve a level top surface with matching head joints and ultimately had to split some surface off of one of the bench stones, all the while concerning ourselves with exposing fresh rock, versus the natural surface, and after lots of trial and error experiments finally achieved a look that we were very very happy with, knowing that there are few sun heated natural rock ledges anywhere that are perfectly flat, and that this stored solar energy heated bench, while not perfectly flat, would be both lovely and extremely comfortable to lay on.

A week or so after the stucco work was completed by our mutual friend Noah Wentworth and with the heater on line, so to speak, I pulled in late one afternoon and let myself in and took a sit and a lay down on the gently heated bench and was very comforted by the beauty and the embrace of the heated stucco and stone.

The natural world does not present itself as level and plumb and square except perhaps in certain crystal forms but even the extraordinary crystal forms of the cooled basaltic columns that I recently wrote about from my Yellowstone trip, are vertical, but never plumb, and are crystalline in form but never regular in shape. We built the core and much of the veneer using very uniform rectilinear shapes and the core itself is based on a very linear and squared off design. To have Lynn request a more rounded and feminine look was a nice challenge and we were very very happy to work with them to achieve this more organic and feminine feeling. Beauty is in curves. When I laid on the curved gray Pownal granite, this grand white lady’s heart was gently pulsing with warmth and with love.

Countless bathers have piled semi-circular terraces of rounded river rock in sequence down the Gardner River to make a series of pools that keep most of the heated water contained along the left bank of the Gardner while at the same time allowing mixing of the cool and hot waters of the two rivers near the center of the Gardner. We sat with proper bathing suits amidst about three dozen bathers and shifted upstream or downstream from pool to pool or simply slid to the right toward the Gardner to find a perfect temperature. The body likes to cook a bit and then cool off and then cook some more. Sliding to the right cooled me down. Sliding back to the left heated me back up. The rocks beneath my sandals and swimsuit were slippery. By sitting submerged with the upper part of my chest and head exposed, I could maintain my position, but the minute I leaned back my head or tried to lay down on my back, the current and my increased buoyancy took over and I would start to slide downstream.

In our masonry heater workshop in Gardiner, the town, I explained how the smoke (Mr. Smoke) moved through the channels and asked folks present to imagine the smoke as a liquid finding the easiest path out, but also being asked (in the contraflow design) to go down a channel when it really wanted (because of its relative buoyancy hot air is thinner than cool air and wants to rise) to go up. The dynamics of an established draft (like the river’s current) could overcome the smoke’s resistance to going downhill and the smoke would in fact travel great distances going downhill or horizontally before escaping up the chimney, all the while giving off heat to the mass and thence to the room. At the confluence of the Boiling River and the Gardner River, the cooler waters of the Gardner were absorbing the heat from the Boiling River as they mixed and the bathers, as well, were like the bricks in our heat exchange channels, raising our bodies’ thermal mass temperatures.

Back at the Boiling River, there is an ancient travertine blowhole like the blowhole of a whale which is empty and dry now. The Boiling River emerges several feet below this blowhole now and has carved through massive shelves of travertine. As the river cuts through and under the stone, it eventually falls in and is further broken down and carved into gravel and washed away. A series of travertine overhangs on the Gardner, formed by the Boiling River, were favorite bathing holes in the hot water, but the Park Authorities regarded them as unsafe so made a decision to dynamite them to make the bathing area safe. Some things are left to evolve at their own very natural pace, and other features of the landscape are redefined with force to make the space more human friendly.

On the quarter mile walk out from the hot springs at dusk along the riverbank we sighted a water ouzel also known as the dipper flying across the little river. Joel Adams, attending the workshop, pointed out to me that the dipper can land in the shallow water and walk under water upstream in its search for food. This was impressive, given my own recent inability to hold my position with hands and feet combined when I tried to go under the water. What a wonderful and amazing niche, skill, adaptation and ability the ouzel must have. I am reminded that in an unused chimney, chimney swifts will settle and build nests well down into the chimney cavity and unlike almost any other bird (one client found a dead duck at the bottom of his 36 foot chimney) have the ability to climb out of the chimney before flying off.

When you look out the South side of John Stacy and Shirl Ireland’s home, you see huge glass windows in a twelve-foot tall ceiling facing due South and looking at Yellowstone’s Northern mountains. Shirl was determined not to cut off the view of the tops of the mountains from any spot in the room as they designed their living space. John had to keep raising the stick on the side of the tall two by four until he reached twelve feet to insure that their spectacular view would be preserved. The beams John used in building this impressive space were salvaged and recycled from an old freight shed further North and down the Yellowstone River. John and Shirl built their last home in New York from a recycled barn and we built the core and bench layout together in that first and wonderful home several years ago. The chance to join them once again in a new location and a new building venture was a great treat.

Below their home the Yellowstone River is about 50-75 feet down. They are perched right on the top of the riverbank. Between the main house and the gallery (the gallery and studio were completed first) is a wooden connector linking the two buildings. At the basement level, however, hand formed concrete stairs allow the huge black culvert pipes from the street to drain off the volumes of infrequent rainwater across heavy rip rap and down to the Yellowstone. On the opposite side of the home, facing the North and the road into Gardiner, there are almost no windows, except for a small kitchen window overlooking the entry door and a large display window and entry in the gallery. Step outside and you are on the main road into Gardiner. Beyond the road everything rises steeply a few hundred feet to the cliffs of gravel topped with a layer of ancient travertine. The Yellowstone River has been carving its way through all of this rock mass for a long, long time. Shops, motels, and houses sit on what little flat terraces there are and beyond the very limited development, the vertical but wide open spaces begin again.

From their house and gallery (Elk River Art) to the school across the bridge is a one mile walk. In the micro-climate of Gardiner, there is almost no snow, so summer and winter, John and Shirl and the kids and two dogs on leashes make the morning walk to the school at 7:30 a.m. and one or both parents pick up the kids at the end of the day on foot or by car. I joined them for the first school walk and found myself a little dizzy on the bridge of the Yellowstone below. I think the high altitude was partly to cause. Years ago we built a heater in the Sangre de Christo Mountains in Crestone, Colorado and our clients there said that they could not get on a roof for a few days whenever they returned to their home because of the altitude adjustments. The Rocky Mountain big horn sheep are oblivious to the challenges of these heights but I understand their numbers dropped somewhat in recent years when a domestic sheep disease infected them and made them lose their balance as well and many could not negotiate the steep cliffs which are their normal habitat and playground.

I drove up on evening with Joel Adams and Clint Dodge to the old travertine quarry on the North ridge above the main road and there got my first look at the astounding basalt formations from which the gateway was built. I began to see that these tightly joined stacked columns of brown basalt, piled like beautiful organic building blocks, were in fact hexagonal in shape. In our rush to get to the travertine quarry in the dwindling light we did not stop to study the basalt columns in any detail, but the basalt infection had clearly started. The basalt columns are twenty or thirty feet high. Each block is a foot or two high and weighs several hundred pounds. Removed one by one they are ready without future work to be placed in a structure like the entry gate.

Why are the pieces six sided? Why the crystalline shape? How did this wonder occur? Google “Yellowstone Basalt Formations” and you will get the story of the Yellowstone caldera (about 1000 square miles) that was formed in a massive volcanic event about 600,000 years ago. Mountains blew away. Ash filled the sky for a long time. Magma flowed to the surface. Some of this magma is basalt. In addition to the basalt cliffs and columns on the hill above John and Shirl’s home, there are more of these amazing columnar formations in the park. In one gorgeous river canyon, the fenced lookout path on one side of the river looks across a gorge a couple hundred feet or more deep to two massive columnar layers of basalt separated by 50-75 vertical feet of gravel.

One layer is near the top of the gorge, so near that John and Shirl once saw adult and young big horn sheep hopping up and down the stepping stones of the columns with a sheer drop to the river below. Because of their vertical separation, the two distinct layers may represent two different volcanic events. Not knowing the definitive answer to the question does not take away from the wonder of what you see and the puzzle of everything unfolding before you. As old as all of this is, you have a crystal clear sense that you are also in a nursery with things being formed as well as being broken down right in front of you. Great rocks fall off the columns into the river and are washed down and crushed and swept away. A few miles away, new different rock is constantly being formed where the hot springs emerge from the ground land making travertine. Old tumble down cliffs of travertine now broken up into huge craggy boulders, some as big as a large cabin, litter an area on both sides of the road in one area of the park. Seeing the difference between the dead and dying and the birthing and living begins to be become very fuzzy.

In one shallow riverbed in the Lamar Valley we see pieces of petrified wood two or three inches long laying on the beach. Giant petrified trees millions of years old, further up in the mountains have been found. One is twenty-six feet in diameter and we are picking up little petrified wood chips to look at just a tiny fraction of that size. A cataclysmic event trapped the living trees in ash or some substance which allowed their entire structure to be preserved as stone, but even as stone, time wears away at the stone and the tiny slivers that we see will soon be turned to grains of sand, not in my lifetime perhaps, but in the lifetime of the plant. One ancient red wood stone stump has been mapped and fenced off. You can see it but not touch it. Earlier visitors chipped away every bit of two other adjacent red wood stone stumps until only this protected stump still stands.

Imagine as a child, your dad coming home from work one day with a huge barrel of rusty metal in the back of his truck. You ask him what it is after he unloads it with a big blue tractor with the forks on it. He says that the barrel is full of huge rusty nuts that the railroad yard was going to throw out, so your dad brought it home. You, of course, want to play with the whole mess and ask your dad if you can and he, being a believer in learn from play, says, yes you can help yourself. In an hour or two you have made a bunch of random piles, but then you discover that you can stack the large rusty nuts pretty much like coins. Not only can you stack them, but unlike coins or gambling chips, the stacks fit together snugly. The old rusty nuts are six-sided. When your dad comes back to check on you, there is the whole barrel laid out in rusty columns a foot or so tall and three feet wide and a foot deep. You have made your own miniature basalt columnar cliff. The Yellowstone basalt columns have neither threads nor holes in their centers and what is more, they are irregular hexagonal shapes, but each piece in each column fits each adjoining piece and pieces, perfectly on all six sides. How and why? One wonderful basalt deposit that we could drive and walk to in the park was called the Sheep Eater Cliffs, named after the members of the Shoshoni peoples, who for hundreds or thousands of years inhabited the high country of the Yellowstone area and included large quantities of the big horn sheep in their diet. They also made extraordinary garments from their thick whooly hides. In addition, they figured out a way of soaking the big sheep horns in the hot springs, to make the horns workable enough to make extremely powerful hunting bows which were said to the finest bows of any ever made in the region.

A single natural segment of a single basalt column probably weighs 300-500 pounds. Such stones, could not, and likely were not, carried by any means or used for construction until the modern era (not forgetting the amazing fitted stone walls and temples of places like Machu Pichu in Peru and the giant stones of the pyramids in Egypt or Central America). Their singular beauty and their magical crystalline storybook forms had to have deeply moved the first Yellowstone inhabitants as indeed it does to visitors now. I climbed on the tumbledown pile of basalt boulders at the foot of the Sheep Eater Cliffs and took several photos. An ancient city of slowly crumbling temples could have stood there. The official geological survey of the area says that the columns were formed not as the lava flowed but as it cooled and contracted. Some of the sources say that water played a role in the rapid cooling and spectacular geometric cracking creating a literal stone honeycomb. An interesting Creationist Web site attributes the rapid cooling to Noah’s flood. What we see today is what remains after the river has carved through the columnar layer formed 600,000 years ago. The basalt cliffs above John and Shirl’s house are but a tiny remnant of a vast sheet of basalt that was once there.

Interestingly, we take our early evening hot springs and travertine and basalt field trips and then come back the next day to work on our masonry heater project. The core has nearly 300 firebrick in it. All were made from ferrous free clays fired at high temperatures. Just as primal fire from the earth’s molten core makes the steaming water of the Boiling River and the basaltic lava flows, our little heater will also hold fire and store heat and warm the home and hearth of those within. The fire in John and Shirl’s heater will also heat a custom made domestic hot water manifold on top of the inner capping slabs twinned to the solar hot water collectors also being installed.

Just as the magma layer of the earth creeps up through the volcanic fissures beneath Yellowstone and encounters massive amounts of ground water which it turns to steam or very hot water, so too will our heater give off its fair share of heat to a much more modest network of pipes laid on top of the heater in a waterproof tray and this heated water will be added to the hot water sources working elsewhere in the house.

When we finish the inner “doll” we lay on strips of mineral wool gasket. (I often ask people to visualize our contraflow heaters as three nesting carved and painted Russian wooden dolls. The inner doll is the core. The next doll is the heat exchanger and third and outer doll is the veneer. Each doll is free to move within the next larger doll. So too with our core). Once we finish the core, we use sheets of ¼” thick mineral wool which has been fabricated for us in Maine and shipped with the other exotic materials to Montana. We separate each doll from the next with strips or sheets of this ¼” thick mineral wool. The blocks of wool made somewhere in Canada are cut down to our thin sheets with a band saw by our fabricator. To make mineral wool, someone takes a certain kind of rock, crushes it and then heats it to extremely high temperatures and then blows air through to create a kind of wool, sometimes with a consistency like cotton candy, which we use in thin layers as a gasket and in thicker layers of a couple inches or more of insulation. The stone from which the rock wool is typically made is Basalt.

We saw a few dark shapes off in the fields which I assumed, and was assured by John, were elk but they could just as well have been cattle, or moose or wildebeest for all the detail I could see. It was dark, of course, when we arrived at John and Shirl’s home in Gardiner and I didn’t really SEE where we were until the next morning when I realized that we were actually perched on the gravel and boulder strewn high river bank of the Yellowstone River which flowed North many, many feet below. The first range of Northern mountains in Yellowstone park loomed directly in front of us five or six miles away beyond dry and sparsely covered sloping land that gave way to trees just at the foot of the mountains. The old flat rail track on the other side of the river which ran to the Park’s Northern entrance is now idle but for joggers and walkers across the river and this line alone was the only man made flat line in view.

On the other side of the house, walking into town with the kids to school, one could see many many mule deer of all ages and both sexes in several yards clearly preferring the green watered lawn grass to the naturally brown and sparsely watered grasses beyond the river. In an effort to tame this semi-arid wilderness, residents had unwittingly invited the wild creatures into their town. I was also assured that the football field, green and watered, was a favorite gathering place for elk herds. What happened when someone wanted to play football I was not immediately told. Obviously, some kind of natural time and grass sharing system was being worked out.

Framing driveways and dooryards everywhere were countless random pieces and rubble piles of travertine stone. A motel with a steep bank across the street and a block away from John and Shirl’s house, had covered their entire steep bank with a “rip rap” of travertine stones, 30 to 100 pounds each. John pointed out travertine tailings spilling over the ridge high above the sparce settlements and homes on the opposite side of the road and said that there was a huge abandoned travertine quarry operation on top of the hill that we could drive to.

John and Shirl had not finalized their pick for a veneer for their heater. Their last heater in Adirondack, New York, had been made with field and other stones they had gathered all summer long along the road with their little pick up truck. They had laid out the rock in four panels on the floor around the heater and bench core we had built together and then had raised the four sides up one stone at a time. That owner built heater (I only helped design the system and build the core and bench layout with them) remains one of my all time favorite masonry heaters. Like this new heater, it was a see-through with glass double doors on both sides, a bake oven on one side and a big heated bench on the side away from the bake oven. I wondered if they were considering the local travertine as their veneer. I was clearly loving it. Blocks and rocks were apparently free for the taking. There were two reasons that John and Shirl suggested that veered them away from the travertine. One was the color. Shirl wanted a stone with some of the same grays and browns that she could see every day looking out over the Yellowstone. As a gifted fine artist, the color palette around her was always subtly and accurately noted and appreciated. They also felt that a light colored veneer would not pick up any solar gain as well as a darker color would. But given the huge amount of South facing glazing they have, plus twelve foot high end and rear walls, which they intended to cover with lichen covered stone veneer, I did not think that a three foot by seven foot South facing end of a masonry heater, light or dark in color, would have much impact on the total solar gain of the living space. I decided not to press the issue. I already knew from emails before my arrival that Shirl and John were leaning towards using a sandstone that they had found that they both liked. In addition, John and Shirl didn’t have any way calculated in their heads to easily turn a largish piece of travertine into a useable 4-5″ thick veneer stone for their masonry heater. Having recently come off the ad hoc field soapstone boulder sawing operation conducted last winter (their summer: March 2010) in New Zealand, the size of the available blocks seemed less daunting to me. For Shirl and John, a rail saw or six foot diameter portable highway concrete cutting diamond wet saw just a phone call away, had not entered into their imaginations and cost calculations. They had found, instead, a sandstone quarry man a couple of hours away with more than one deposit of beautiful stone. With a bucket loader or other similar large piece of equipment, he could move into his quarry and peel up huge sheets of sandstone three or four inches thick and then back at his shop using saws and hydraulic splitters, could turn it into any reasonable modular size one desired.

In John and Shirl’s original home, they had salvaged a weathered timber frame barn for their structure. For this home, John found some wonderful old long uniform lodgepole pine logs that had been part of the structure of an old rail shed and he had salvaged them for all of his posts and ceiling beams. Against this antique peeled log background with plaster ceilings and future lichen covered grey stone walls filling the vertical spaces, they had decided on the slightly more formal and subdued look of the quarried sandstone, to the more random look of any kind of field stone. This choice did not stop an Eastern States stone lover or his two Montana based workshop attendees from wanting to see the old travertine quarry and within a day or two of our arrival, Joel Adams brought me and Clint Dodge, the other attending mason, up the ridge around dusk in his four wheel drive vehicle. Riding with Joel, a hydrogeologist, who is also from the Yellowstone area, I soon learned to keep my stone formation wisdom to myself, but Joel was very gentle in the sharing of the wealth of knowledge that he had about such things.

The first time I saw travertine blocks in quantity was in the buildings of the famous Getty Art Museum on the outskirts of Los Angeles. All parking at the Museum is at the foot of the tall hill that the Getty sits on. Smooth automatic rail cars take passengers up the hill to the large cluster of buildings, terraces and gardens. No traffic distracts the viewer from the powerful impact of the magnificent stone buildings. The huge travertine blocks of the museum structures, each placed in a different vertical plane from any of its adjoining neighbors, were absolutely unforgettable. I imagined that the rock probably came from far far away like from Italy and indeed, I believe that it did. I did not know at the time that the coliseum in Rome is made mostly from travertine. I had read that it also has a huge quantity of red bricks in it.

I have worked with very old limestone blocks recycled from a long disappeared barn with only the foundation remaining in New Jersey. I have seen an inordinate number of lime kilns populating the roadsides of Blairstown in Northwestern, New Jersey. I have visited six or more of these kilns. The largest are twelve feet tall and twenty four feet long with a giant stone bowl shape on the top where limestone chinks and coal were laid in alternating layers and burned from an ignition port below over a period of many days to produce quick lime for agriculture and for mortar. The abandoned travertine quarry site in Gardiner, Montana seems to cover one hundred acres or more. At the old quarry site we found huge piles of scrap and one block with holes drilled in it and a gorgeous large set of iron feathers and wedge still stuck, rusting, in one of the drilled holes…a block that was never fully split out. We found other large quarried blocks that had never gone to market. At one point in the quarry we stood against a sheer sawed wall perhaps twenty feet tall. This wall, and the block it contained, had to have been cut with a diamond encrusted cable or “wire” saw. Two holes are drilled beneath a large block, one at the face and one at the rear side of the block. The two holes have to line up in the same horizontal plane. Where the two holes intersect, a cable can be fed through one hole and out the other end and then pulled on tensioned wheels to undercut the huge block. Once the cut is complete a third hole can be drilled down opposite the side wall hole from the top. Once the top bore intersects with the bottom shelf cut, the wire cable with diamonds can be fed through again and the vertical cut can be made. When this cut is complete, the huge block “falls” about an inch to the floor of the quarry shelf and the block is now free for further recutting and transport. Our friends at the soapstone quarry in Quebec, at Les Pierres Steatite, now use such a saw to cut out their quarry blocks. They used to have to drill many side by side holes with jack hammers to free a block, with much more cracking and damage than a wire saw ever creates.

Had I been in charge of the Getty Museum project, I think I would have lobbied hard for using the Gardiner travertine, if there had been enough of it, because of its beauty and its American origins. The Gardiner travertine came in shades of white and pink and beige. One block clearly had a blow hole from a steam vent in it, on an identical but smaller scale to the old steam vent holes looking like a beached whale head we had seen at the Boiling River hot springs a few miles away. It suddenly struck us that the same process going on at the Boiling River had previously happened here many centuries earlier. In addition, the rock seemed to contain evidence of organic forms in it, like the calcified skeleton of a coral reef. How life could co-exist in the formation of travertine depositions and boiling hot water and steam remained for the moment a mystery. We brought back in Joel’s vehicle a few choice souvenirs from the old quarry knowing that they were too heavy to carry back along with clothes and a precious few mason’s tools in a bag with a fifty-pound limit. For a mason who normally travels with a three quarter ton pickup truck full of tools, I had sent John a long tool shopping list of my needs and had packed a tiny bag inside my larger bag with a torpedo level, three carbide tipped tool bits, three trowels, a grinder blade, a mason’s ruler and my favorite diamond covered grinder blade, dust masks, ear plugs, glasses, and a small nylon weighted hammer.

Deep below Yellowstone Park are fissures connecting to the molten lava far below. The lava works its way up through the cracks to a point where it encounters calcium rich ground water and sends this water under pressure up through more fissures and steam vents in the ground. Old vents are constantly closing and new vents are constantly opening. This is a dynamic process. Witnessing the changes makes one wonder about the uniqueness of Old Faithful which has kept a reasonably steady schedule now for hundreds of years.

In our masonry heater we used quick lime in our mortar mix and we used a wonderful insulation block made in Denmark called Skamol (Ska=Scandanavia   Mol=Insulation) made out of calcium silicate. Like the calcium carbonate travertine rock formations, the manufactured calcium silicate block insulation is full of millions of tiny holes. The calcium forms the skeleton around the holes. It is the air trapped within the skeleton which plays such a big role in insulating the mass above it. In our own bodies, our skeletons and bones are also constantly being worked on until we begin to lose calcium. Our bones, like the travertine and the Skamol board, are also full of holes, with our own body’s life building fluids moving around in them. My brother, Howard, for years worked as a senior scientist for a firm in Wisconsin called Lunar which measured bone density with sound waves. This equipment came to be used around the world.

I learned from John that he had built his previous heater and the foundation for this heater using only Portland cement and sand. Lime added to the mortar gives it more plasticity and flexibility and setting time, but John’s own evolution in isolation as a heater builder had not produced any problems for their earlier heater or for this foundation. His experience provided us with a good lesson of how following an independent evolutionary path can sometimes produce good results.

One evening after work, when Clint went off again to the Boiling River Hot Springs, Joel Adams and I drove a bit further into the park at dusk for Joel to show me the living travertine formations at Mammoth Hot Springs. Ready for winter, about to rut elks were everywhere taking over the lawns of the buildings at Mammoth Hot Springs. Large bulls were few in numbers but each had generous harems of cows and calves in their care. The green grass lawns, not the tourists, the cameras, or cars were the attraction for the elk. They put up mostly with all of this nuisance for the grass but would occasionally push a visitor into one of the buildings if the mood struck them. Orange vested Park Rangers posted themselves near a pair of sparing bulls to keep the people away from the action and to protect all the players. The gift shops in the park are full of gorgeous wildlife photos of elk and grizzlies and buffalo and wolves for hundreds or even a thousand dollars or more, so all of my snapshot efforts, by comparison were a little silly. On a drive back one night through Mammoth Hot Springs after dark, we found the big elk that John had been looking for but my camera, without a red eye mini blink, made basically a wild guess as to what I was shooting. Only digital enhancement could make a real photo out of the image. So much for my efforts to document a big bull elk. John Stacy told me of a hike he and Shirl had taken within view of their home and within the park. There on the high plateau were hundreds or thousands of elk antler drops.  All of them belong to you and citizens such as me, and every antler is illegal to remove. Just seeing such a boneyard would be enough of a gift for me.

At dusk at the end of an October day in Mammoth Hot Springs, the crowds have thinned out considerably. On the boardwalks snaking around and through the hot springs there is a German couple with their beautiful daughter. A Japanese photographer with a tripod is carefully crafting some memorable shots. I am quietly overwhelmed by the beauty and magic and mystery and wonder of what I am seeing.

Terraced growing deposits of travertine stone are everywhere covered with steam and a thin sheen of rippling moving water that has emerged deep from within the Earth. It is also a ghost land of sorts. Trees give way to the heat and die but stand as skeletal sentinels where they once in turn grew. But the stone is not the white or grey or pink stilled travertine that we saw in Gardiner. Here, the living deposits are teaming with heat loving algae and bacteria giving a huge array of living sherbet colors to the soft fountain displays in front of our eyes. Now I can see why some of the rocks I picked up at the Gardiner quarry above John and Shirl’s home seemed so full of life. They had been alive. They were formed with living creatures fully participating in their manufacture. Calcium rich water deep in the Earth comes to the surface as a steam and these creatures live in and on this water and in and on this stone as it precipitates out as calcium carbonate.

We stood mesmerized alone at one twenty or thirty foot diameter breast shaped mound above. From atop the mound, a clear, very warm liquid bubbled out and shimmered and rippled down the flanks of the mound, sighing and whispering as it moved. From her fire and water belly deep, deep below, this Great Mother was sending her hot fluid building blocks of life to the surface, and life at the surface was abounding with these extraordinary pastel living sherbet colors. Again, we were stuck by how the living and dying around us are combined. The trees give way to steam and rocks and algae and bacteria. Other forms of water and algae and bacteria worked in the trees when they were building their cells and leaves. This living and dying at Mammoth Hot Springs brings us mere humans to this place in droves from all over the world. Some of us are foolish enough to think that this is just another five-minute photo opportunity on the way to the next fast food steam stop, but it is much more than this. Sixty percent of the world’s thermal spring and steam vent activity is going on right here in Yellowstone Park. This is wonder, a deeply, deeply humbling wonder that we feel. What springs feed the calcium beds in our bodies? What powers the limestone in our mortar to workable lime? What form of calcium was transformed by technology in Denmark into remarkable non-toxic hand sawable insulating block? How does a masonry heater heat not only our homes and perhaps some of our hot water but also feed the waters of our hearts and souls? John and Shirl knew that it would do all of those things. They had lived with such a heater before and when it came time to leave Adirondack, New York, one of the hardest parts of leaving was to walk away from their masonry heater.

Now they have another masonry heater underway. In a region rich in basalt and travertine and sandstone, John and Shirl had chosen standstone for their heater. While I write this blog, John is finishing up the sandstone veneer. All the pleasures and comforts that they recall will come to them again soon this winter and for many winters to come in their home perched above the Yellowstone River.

Heikki, although trained as an architect and also working as the editor of a Finnish magazine called Muoto (Form) started with a research interest in masonry heaters and then became much more deeply involved with masonry heaters when he formed his own small manufacturing and design company in Finland called Tulisydan Oy. For the past fourteen years, Heikki has been the head of the masonry heater organization in Finland and for the past decade and longer Heikki has been working to refine the design of a mason friendly, user friendly, relatively low cost, high efficiency, clean burning firebox cassette and core system which anyone could use and from which expect excellent results. Recently, Heikki produced ten units of his design as a pre-production prototype run and sent two of these units to the States. One was to be built and displayed and fired at Wild Acres and one was to be sent to an EPA approved testing lab in Washington State for emissions testing.

At Wild Acres, we built up the cassette core in two days with several professional masons in attendance and then started firing the unit. Heikki immediately noted from the large amounts of moisture boiling out of the ends of the logs that the wood was not dry. Given the short time of the Wild Acres event, we knew as well that we would have to burn the unit very aggressively to dry out the clay mortar in order to create an atmosphere in which the unit could burn cleanly and well. Once we were able to dry out the unit itself and find better wood, we were able to get the unit to burn much more satisfactorily. No fewer than seven other projects including three other heaters, a cooker, a bake oven and a smoker and a “rocket” Contraflow heater were also being built in a workshop format, so the attendee population was widely dispersed around all of these projects during the event. A cleaner burning and cooler burning masonry smoker was built and used which grabbed the attention of everyone there along with the annual building of a bake oven which produced pizzas for the annual outdoor party in the work area at the end of each Wild Acres session.

Heikki also gave a ninety-minute PowerPoint presentation on the history and state of the art of wood burning and masonry heaters in Finland. With handheld cameras, the presentation was recorded on video and will likely be available through the MHA Web site in the future. Before his presentation, I was unaware that Heikki has fifteen different wood fired appliances at his summer cottage in Finland. These include indoor and outdoor ovens, saunas, fireplaces, cookstoves, etc. His curiosity and need to perfect a way to burn wood cleanly and well have clearly been a driving force in his life for a long long time.  I also learned from Heikki that he advises against storing wood inside the home as he is concerned about the mold that can dry out on the wood fuel and enter the house atmosphere and affect children’s health. He advised that wood should be split and immediately put under cover in an outdoor well-ventilated wood shed and then brought into the home as it is needed. It is clear that the wood species available in Finland are primarily white birch and softwoods, more prone to quick rot than many New England hardwood species, but his input was significant and welcomed.

The first half of his presentation was historical and cultural and the second half of his presentation addressed the more technical questions and challenges of our times.  He described clearly the problems of particulate emissions and how to work to lower the emissions of both large and ultra fine particles. He described in detail how wood burns and gasifies and how it is necessary to capture and burn the gases in a manageable and clean way and then presented graphs and drawings showing how Contraflow heaters were once built and how his new research is showing how they should be best built today for maximum efficiency and lowest particulate emissions.

The current design he has worked out uses a thick inner heat exchange wall and a thick slightly separate outer or veneer wall with a total wall thickness of close to 10 inches. He pointed out that in a well-insulated modern modest Finnish home, that such a heater can be fired once a day every other day and keep the house toasty and warm. Americans are not yet building such modest high efficiency homes in great numbers but it was hopeful to see from his work, how a high efficiency system such as the one he has developed as a core, could be adapted to work cleanly and efficiently in our current North American house designs. Particularly impressive was a graph that showed a nearly unchanging steady stream of heat output over a twenty-four hour period when using one of his designs.

In addition to a long history of masonry heater designs, Heikki also showed us photos and told stories of several commercial artisan bake ovens that he had built, many in a workshop format, throughout Scandanavia. One of the ovens, which he designed and built in a workshop format, he described as a two-tier Finnish Contraflow design. The fire is lit in the afternoon and burns until it is out two or three hours later. The heat is stored in the mass and evens out over night. The baker comes in the next morning and then bakes all day long, doing as many as seven loads of bread. Heikki said that this Swedish oven can bake 500 kg of bread from one two hour firing of 70 kg of wood.

After Wild Acres, Heikki stayed a day with Tom Trout and then flew out of Ashville to Washington. Albie drove twelve hours to New Jersey and left his fully loaded truck there and then flew out of Newark to join Heikki and Tim Seaton in Spokane and Colville, for a week of testing at Ben Myren’s lab. The first core was packed up and crated for a rest in New Jersey and then came home to Maine with Albie where at some point in the future we hope to reconstruct the system for our crew here and do some more testing with it.

This trip, I predict, will prove to have been a very important trip for the future of masonry heaters in North America. His contributions here and in Finland have been very significant and we are very grateful that he agreed to spend another two weeks with us here in the States during this past April. Keep your eyes peeled here and on the MHA Web site for news about Heikki’s video recorded presentation and look as well for an informal report on our testing experience in Washington State at Ben Myren’s lab.

Although we decided to use a firebrick and castable refractory core, with a stuccoed brick veneer with rounded corners, Sampsa had been bitten by the soapstone bug and he kept his ears to the ground for rumors of soapstone in New Zealand. He learned that somewhere in the northern part of the South Island, an entrepreneur had located soapstone and had done exploratory surface removal of some sizable pieces and that the cut offs from this exploratory quarrying had created enough soapstone to fill two or three pallets. The pallets of soapstone were near or at a yard that fabricated beautiful flamed basalt floor tiles.

From a great distance, I was very nervous about thinking that we could fabricate a New Zealand soapstone heater from an untried source of stone with a tight timetable and almost no serious information on the stone in hand. When I landed in Queenstown, Sampsa had, in fact, acquired a rough cut small slab sample of the stone about 40mm thick and thought there might be a possibility of getting the basalt folks to cut up the two or three pallets of stone for us into workable slabs. After chasing tools and materials for three days prior to the workshop and believing that a soapstone bird in the hand was worth two in the bush, I urged Sampsa to just get the stone to the job site as fast as possible and that after looking at it, we would chart a course as to how and if it could be transformed into useable stone for his project. The costs for the unseen pallets of stone were not high and the transport costs seemed reasonable to Sampsa.

With a quick phone call, Sampsa got the stone on the road. The next day, two drivers showed up from the nearby town of Alexandra. One had the stone on board his freight truck and the other had driven an all terrain large forklift up from town a few miles away. The soapstone chunks ranged in size from a hundred or more pounds to a thousand pounds and from a foot to three or more feet in length. Each piece typically had one smooth sawed face and the rest was rough and raw. There were almost no slabbed pieces at all. Our sample had allowed us to do some wishful thinking, but anything we were planning to do with this stone was going to require a lot of work. The drivers off loaded the soapstone pallets and, with the good natured helpfulness that so many Kiwis displayed throughout my stay, agreed to bring up all the pallets of brick and firebrick and mortar that were stacked on the ground below the house to a narrow strip of flat ground just by Sampsa’s back door, saving us many trips up the little hill to his house.

We knew that we could not fabricate a quantity of slabbed and polished stock with the tools we had in hand, so calls were made to a local concrete sawing firm with portable equipment. They were happy to come look at our pile of stone and arrived promptly the next day. They were not in the least bit cowed by the challenge but said that we would need to acquire a large concrete slab to anchor the portable rail saw to before they could come and start the cutting. Sampsa had built his house with two large recycled concrete slab walls in his home so he quickly placed a call to the concrete recycling folks and they had a very affordable reinforced slab six or eight inches thick and about six feet by eight or nine feet long. The slab had a hairline crack in it making it unusable for any purpose other than a creative venture like ours. Sven and Chris quickly hooked up Sven’s utility trailer to his four-wheel drive vehicle and down the road they went to the concrete facility an hour or more away. A couple hours later they were back with a huge concrete slab strapped and perched on pallets in Sven’s trailer. The slab weighed several thousand pounds and we, of course, had no power equipment to unload it, so began a creative process of jacking, fitting rollers, tying straps to the pallets of soapstone and driving the trailer part way out from the slab, leaving it tipping precariously off the end of the trailer. A bit more jacking and shimming and the slab was perched at a good higher angle free of the front of the trailer. Sven pulled his vehicle and trailer ahead. Seconds later, a loud thud and a cloud of dust saw the slab flat on the ground, none the worse for its fall. Sven’s trailer also emerged unscathed. A few more minutes and the guys had it perfectly level and the call went in again to the sawyers to come and join the party.

They arrived the next day with vans and a huge generator and a utility trailer full of blades and a large portable saw and two heavy concrete blocks which we drilled and anchored to the leveled slab. Chris and Sven and Sampsa wrestled slab after slab into position under the blade and using blocks, poles, straps and clamps, anchored each large chunk of soapstone into position and the sawyer with a lovely hand held joy stick, moved the wet saw four foot blade into position and slowly cut through each stone, cutting 40mm to 75mm slabs as per Sampsa and the design team’s instructions. It took a day and a half to cut through the two pallets and Sampsa hoped he would have enough stone not only for his own project and for steam rocks on top of his sauna stove, but would also have some rock slabs left for other guys in the group to access when they built their own heaters.

Inside the home, progress on the heater never slowed down and we were ready for the oven shelf slab before the heavy equipment ever arrived, so for a few hours, Sampsa and Andrew, using a skill saw, grinders, a rotary hammer, our rented diamond wet saw and various sanders, fabricated a large shelf for us from raw soapstone stock. The rest of the trim for the base, the bench stone, and the cap course of soapstone all came off the portable Soapstone Factory production line that we had created. Every available hand was pressed into use to take the raw slabs that had been cut on the big portable saw and to turn them into precisely sized, shaped and polished pieces for the stove. This meant a minimum of four men working with one measuring and designing shapes, one working the l4″ wet diamond saw, and two men sanding and shaping and polishing. This left Matt still free to photograph, Malcolm to tend, Sean and Liam to keep laying bricks, Albie to orchestrate quietly the whole endeavor and try to keep his mouth from falling too far open in astonishment at what the crew was attempting and succeeding to do, and one spare person to step in wherever necessary. I felt like I was at an Amish barn raising. Everyone worked seamlessly and knew that a great deal had to be done and done well in a very limited amount of time and so that is what they did. I worked with Chris Naylor, our gifted builder and wood carver, at designing the templates for a three-piece free form hearth which Chris and I worked together on to cut out and polish. The rest was handled by the Sampsa’s dedicated Soapstone Factory crew.

At the end, we had a soapstone hearth, a soapstone oven shelf, trim around the base and a trim course around the top, rabbited to receive a capping plate of steel and a trim course for the chimney. There was not a lot of useable stone left over. The factory had worked to capacity. The concrete sawyers packed up their gear and left but not before coming in to admire what they had helped create. We made several trips to town to look for the perfect sanding tool for this particular soapstone and finally settled on a kind of dense plastic fiber paint stripping wheel which worked the stone quickly to a modest muted polish without gouging the stone or creating too much mess. Sampsa was very happy with this softer, not high polish, finish. We were confident that once the stucco was up, the gray and the white together would be stunning. We saved some of the soapstone dust from the wet saw to make up a waterglass and soapstone dust mortar for fine line head joints on the top trim course.

My favorite stone from the various blocks we worked had a kind of leopard markings quality to it and I decided in my own mind to call it snow leopard. I brought home a piece of it to carve for a friend who is receiving rocks for his heater from all over the world. With my soapstone chunk and a gift Scutch hammer from the crew and as much wild organic Clyde Central Otago thyme as I could pick and process and bag with labels and even a price to pass through customs, my bag was still under the limit of fifty pounds. Sampsa had proudly realized his soapstone dream and we were all the better for it.

Eventually, an extension to one side of the cookstove was added with a tin lined copper reservoir for heating domestic hot water. Water was poured into the reservoir with pails and could be drawn out of the reservoir with a long handled pan or through a small brass spigot in the front of the stove coming through the reservoir and castings.

Our Norridgewock, Maine farmhouse, built in the l830′s, boasted the first year round running water system in the area. A spring on the bank near the house was tapped with a pipe which ran down a hill to a hydraulic ram and pressure building up inside the bell shaped ram allowed the water to be forced back uphill in a smaller diameter pipe to an oak barrel in the kitchen. An overflow pipe ran out of the top of the barrel back to a safe dump zone outdoors. In the right light you can still see the small blocks of wood in the wide board wainscoting where the old pipes came and went. Twenty or more years ago, a woman in her sixties or seventies came to the door once who had lived in the house as a girl and she was able to describe in detail exactly where the barrel had stood which confirmed all of our detective work.

This system meant that the house had fresh water in the kitchen all year long in a never-ending stream, but this system only brought the water into the house. It did not heat the water or move it to the cookstove. The next breakthrough in hot water design came with the invention of a brass water coil for the inside of the cookstove firebox linked to a thirty gallon hot water tank on a stand next to the cookstove and a running water supply keeping the tank and water jacket full. Copper tanks without insulation almost never overheated as they could radiate more and more heat from their surface as the firebox heat in the stove increased in intensity or duration. These systems delivered hot water very effectively without safety valves to any part of the house that had plumbing.

I used to go to a hardware store in Skowhegan, Maine that still had l80 degree threaded brass elbows designed for fabricating the brass water jackets. A photo of water jackets we’ve used is shown below.

When we experimented with a variety of more “modern” cookstoves, including the Waterford, Stanley from Ireland, the Stanley included a domestic hot jacket option that sat in the rear of the firebox and many customers chose to include this option in their Stanley purchases. For many years, Maine Wood Heat was the North American importer of an Austrian built cookstove with a very large water jacket that completely surrounded the fire. The Austrian Tirolia had insulated sides and rear and top and an insulated lid so it could be used even during the summer for short burns. In one hour, we could heat an eighty gallon domestic hot water tank with a gravity thermosyphon loop going to the tank upstairs. We had an aquastat (water thermostat) in the tank that allowed the tank to get to the desired “high limit” that we had set, and then it automatically forced the house radiator circulator pump to go on. Whenever the domestic tank got low in heat, the next batch of hot water production always went first to the tank and then to the house radiators. We cooked, baked, heated domestic hot water and the house for years using this central heating cookstove. We still have people calling us who have had their Tirolias in use for twenty years or more.

The Austrian company ultimately went out of business and we also decided to stop selling them when we realized that we needed to make a choice between a low emissions system like a masonry heater, versus a higher emissions system like a water clad firebox of the Tirolia. Once we switched our focus entirely to masonry heaters, the interest from the public in heating domestic hot water or radiators from the systems we were building did not cease. In the very early days of masonry heaters in Maine in the late 1970′s, I remember a heater built near the State Capitol of Augusta that someone had run large diameter hot water pipes throughout the system thinking that if a little bit works then bigger would be much better. In the first year of operation, a leak somewhere in the system had destroyed everything. Steam of course has explosive force and is highly dangerous and any inclusion of water in a masonry system has to be carefully designed and understood and executed. Over time we found that we could build modest sized stainless steel heat exchangers and place them directly in the fire of a brick wood cookstove and get good results, albeit with a dirtier burn than a firebox without a water jacket. We also found that if we put a stainless steel water jacket in a non-direct or “remote” location behind a layer of firebrick in the throat area of our heaters, we could get a trickle charge gain on domestic hot water production without lowering combustion efficiency. Other people have developed different systems which have done a similar job of modest domestic hot water production. In one or more instances we designed water jackets that were made of a copper tubing layout on top of the inner capping slabs. We designed but did not build the idea of such an array inside a stainless tray on top of the capping slabs with the tubing surrounded by glass beads or marbles or stainless steel or steel shot and to get better conductivity to the copper tubing. All such designs called for installing a large domestic hot water tank on the next floor level directly above the heater and/or cooker guaranteeing a thermosyphon non-electric transfer of heat to the tank.

In the event of a power outage such a set up guarantees that there will be no overheating of the coil or hot water tank because of its large capacity. We have always discouraged the use of any domestic water jacket system coupled to a tank located below the heater and requiring a pump for its safe operation. In New Zealand, it became very clear to Albie that New Zealanders want to heat hot water from whatever wood burning appliance they are using. In the home that Albie stayed in with Chris and Debbie Naylor, there was a blue enameled stove in the kitchen with a refractory lined firebox, and a horizontal baffle above the firebox. At the throat of the baffle was a stainless steel secondary air tube for more complete combustion and at the rear of the firebox secondary chamber was a domestic hot water jacket, which in New Zealand is called a “wetback.”

Sampsa plans to have some solar panels for domestic hot water in his house design but he also wanted to heat some hot water from his masonry heater and he wanted it to not only heat domestic hot water, but to also send heat to a large room on a level below the heater and to a bathroom two partition walls beyond the heater. This is why the heater is being built in the lounge, which you can see in the house plan above. It is very common in Germany to have cast iron and firebrick central heating boilers built inside of ceramic tile Kachelofens. This puts a traditional radiant mass heater in a central living room in the house but also sends heat to a number of remote rooms and also likely can produce domestic hot water. It is unlikely that such central heating Kachelofen burn with the efficiency or cleanliness of a standard non-water jacketed “Grundofen.”

In Finland, Sampsa found a company that made a cast iron heat exchanger that eliminated the presence of hot water entirely from the heater itself. Instead, the system he found replaced the top capping slabs of castable refractory with two “needled” plates of overlapping cast iron that at the end of the flame path near the top of the heater, converted the super heated gases to hot air in a plenum above the plates and sent the hot air out to a remote box to be mounted on a wall in an adjacent room with its own air to water heat exchanger in it. This is just the opposite system from what one sees in the local Prompto quick oil change garage. There, an oil or gas boiler in a utility room heats hot water. The water is piped to radiator units near the ceiling equipped with fans. The fans convert the hydronic heat in the finned radiators to hot air heat. This, in combination with overhead gas radiant panels, keeps the garage warm without requiring any “in-the-way” floor border radiation units.

With the cast iron “needled” (or up and down “nail bed”) design, the combustion efficiency could still be kept very high and the danger of steam explosions in the heater eliminated while making the always difficult transfer of heat to remote rooms possible. You can see another photo of this “needled design” in a previous blog article about the panorama door construction series. Sampsa is hiring a heating engineer to assist with the placement and hookup of the external heat exchange system. He already has the radiant floor tubing laid out for his remote bedroom downstairs and his remote bathroom and last week the earth floor in the living area where we built the heater were installed adding almost a foot of height to the level we had worked from. The house designer partner Sven (of Sven and Sarah Johnston) who is also in charge of the plastering and earth floors has now put in most of the earth floors and commented that the heater looks a lot shorter with the floor now pretty much in. Sampsa wrote recently as well and sent a photo of his mom Seija, who lined up all my flight and hotel reservations, sitting on the soapstone bench at the corner of the heater. You can see the new floor height under her feet.

It will be a while before the heater is plastered and the heat exchanger is hooked up. Once the chimney is in place and the heat exchanger is hooked up, it is likely that the heater will be fired a bit to “settle” the unit and have any movement and shrinkage occur before the plaster or stucco is applied. We have sent information on traditional Swedish Kachelugn stuccos to the guys in Clyde. This information was supplied to us by our old friend and colleague in Montreal, Marcus Flynn who alone at Pyromasse, builds some of the most beautiful brick heaters in the world. We will keep everyone informed as the heat exchanger performance unfolds and is documented. The heater efficiency and emissions is all scheduled to be tested once the hook up of the heat exchanger and the chimney is complete. If the system works well, we have made contact with the Finnish firm and are prepared to make it available to clients here in the States. Please give us time to test the system and firm up all the information. We will report on the progress and availability of the system in future blogs.

Near the end of the workshop we had a long discussion with all the members present about how to design homemade effective hot water systems into a masonry heater after they made it quite clear that they wanted to produce clean heat and domestic hot water from one fire, not two. Keep your eyes peeled for news of future developments.

Meanwhile, we will report soon on the amazing securing of a quantity of soapstone for Sampsa’s project and the transformation of this soapstone in just four or five days into fitted polished slabs for shelves, benches, base board and cap trim for his heater. This only happened because of phenomenal co-operation and effort on the part of all the members of the workshop team. While two masons did the yeomans work of laying bricks and another member or two did tending and mixing, every other available hand was involved in securing the soapstone, finding a portable rail saw service, securing a heavy concrete slab, positioning the slabs for the big portable saw and then cutting slab after slab for two days and then processing each slab into the finished pieces. You can see the soapstone trim in place behind Seija, Sampsa’s mom, in the photo above.

Look for the story on how it was all fabricated next.

The masonry heater we built in Lincolnville worked well for about twenty years. Our friend Chris Chatfield called one day and said that he was doubling the size of his little Cape and wanted a second heater built and while we were there could we look at his original heater. As we built the new heater with an Albiecore in the expanded section of the house, we also assigned one mason to gently open up and repair the firebox of the original heater. Both the rebuilt heater and the new heater are now being used in the Lincolnville home. The metal tubes bringing in the secondary air had plugged or eroded so we took them out during the rebuild.

Since that very first heater, we have tried to continually improve our system, especially in the firebox and over the years developed the Albiecore concept based on the idea of making all the firebox and fire tube components easily repairable and replaceable. Recently we increased the number of floor components from four pieces to eight so that the floor could be easily replaced at any time. And most recently we have begun to do prototype firebox work for certain clients who wanted to be willing experimenters with us using over fire air.

About ten years ago I was in Finland visiting Heikki and at a mason’s supply and building center, we attended an open house where several masons had built up samples of their masonry heater work for new house customers to come in and see. Customers were meeting the masons and picking both craftsmen and designs that they liked. I noticed that a number of the fireboxes offered very simple over fire air supply ideas. All were quite small.

About fifteen years ago, Heikki started experimenting in his shop with a firebox design idea to create a cassette that would be an insert that would feature the cleanest possible burn. His design work matured over fifteen years and had over 1500 computer monitored test burns in his system as it evolved. The system now has a worldwide patent and is in the prototype pre-production stage. We expect to receive two of his prototype cassettes shortly and one of them will be tested for emissions at an American West Coast lab run by Ben Myren. A second unit will be shipped to the annual MHA event in April at Wildacres in Little Switzerland and Heikki and others will build up a heater using his cassette and do some test burns on it. Heikki will also lecture to the entire group on his research work. I will then take the cassette home and install it sometime soon in a test unit here or in a permanent wood burning heater, perhaps a soapstone heater that we are working with.

A few years ago, I went to Holland on my way to visit our wood fired oven partners in France, accompanied by my daughter Anna. We wanted to see the work and shop of a remarkable masonry heater designer in Holland called Fetze Techlar. He had just expanded his little shop into a rented disused creamery and had a production line set up being run by his son. Fetze was making a number of stacking modular heater lifts in a variety of ceramic colors, which you can see on the left. All the colors were standard mortar colors ranging from cream to red to blue and he was using a castable refractory system and molds that allowed him to cast beautifully colored refractory elements that looked like fired ceramics. Aside from having designed a system that used no mortar, Fetze was also experimenting with a second or third generation of over fire air ports which was produced in a heater at his son’s home that we visited, one of the cleanest looking and beautiful burns that I have ever seen.

At Maine Wood Heat Co., Scott Barden needed to build a small heater for his own home, so inspired by photos of some of Fetze’s work, he went about designing and building a soapstone veneered masonry heater with firebrick and castable refractory guts which included secondary air over fire air ports. He has since built a few more of his heaters for clients of ours and each have included these over fire air ports. Once the fire is underway, the door drafts can be closed and then all the air comes to the fire at the level above the logs where the gases are hot and rich and looking for oxygen. The burn is quite clean. The burn time is extended and the heat absorption is extended as well.

When I go to babysit my grandchildren at Scott and Cate’s home in the winter months, we always light the fire together and are mesmerized by the beauty and warmth of the heater and its over fire burn. Sometimes it is hard to get a clear view of the fire, because June Bug, their dog, sits directly in front of the door for a half hour at a time looking at the fire and soaking up the warmth.

We will be building a Scott design custom soapstone veneered heater in April for our friend Marty Cain before Wildacres. We are building the unit as a permanent unit in Marty’s Black Mountain cottage home. We have cut both the core and the veneer here in Maine, and prepped it all as a kit for a three-day hands-on workshop which we estimate will cost about $300.00 to attend. For this unit, based on Scott’s heater, we have again worked with over fire air and we have quadrupled the amount of air we are bringing in over the fire comparing this unit to Scott’s heater in his home. Chris Pelletier at our shop designed a very nice pair of adapted small soot doors as the secondary air draft controls. This workshop will be documented and presented in a future blog.

Last year (2009) we built two prototype full-sized fireboxes in heaters for clients who wanted masonry heaters and who were willing to experiment with us to try to achieve a cleaner burn. Both heaters used a similar system of bringing in air through the ash box door, closing off the grate, except for ash dumping and removal, and bringing combustion air in under the firebox floor and between the inner and outer walls of the firebox to be directed back into the firebox higher up in a series of small ports spread around the firebox. Both clients have kept in close touch with us and report good satisfaction and pleasure from their over draft fireboxes. The doors stay cleaner. The fire burns longer and the upper chamber oven temperatures are higher. The couple in Strong, Maine are routinely baking wood fired pizzas in their upper chamber oven from the accumulated heat of the fire.

In New Zealand, with an all-handmade masonry heater construction workshop, Albie decided to build with his students another version of a firebox with lots of over fire air as an option (the same firebox can be converted at any time to a through-the-grate air delivery firebox). We measured the grate that Sampsa had bought and determined that we had twenty-four square inches or more of opening in the grate through which air could pass so we decided to design a secondary air over fire air delivery system of about twenty-four inches of air. This would be significantly larger volumes of air than our first experiment in Lincolnville, Maine.

The firebrick that Sampsa had purchased was the same length and width dimension as standard American firebrick (4.5″ by 9″) but the thickness of the large firebrick was 75mm (2 l5/l6″) and the thickness of the thinner firebrick was 1 3/8 inch or 35mm. We had lots of height in the cathedral ceiling room so we decided to build a three brick thick firebox floor. The first layer of thick firebrick bridged over the rear channel and along the sides were cut at a skewed angle to allow the expanded room we normally leave at the base of the heat exchange channels to keep “Mr. Smoke” from getting his shoulders stuck as he makes the difficult turn upside down to enter the base channel and find his way in the dark to the chimney.

The next layer of firebrick was the 35mm brick and with this we created a sunburst pattern so that arranged around the two sides and the rear of the firegrate opening we were able to lay out eight three inch wide channels or “rays” leading to the side walls and rear wall. We made the firebox walls out of two layers of firebrick turned on edge and cut slots into the inner layer of thick firebrick so that the three-inch channels extended vertically much of the way up the firebox wall. Opposite these eight three inch channels we made three stacking one inch square openings for a total of twenty-four square inches of openings around the two sides and rear of the firebox. As you can imagine, cutting this system was very labor intensive and required a lot of patience but we had very gifted craftsmen on the site able to handle any challenge.

The third layer of firebrick we again made out of the 785mm thick stock and completely covered the floor. We worried a little bit about ash getting down into the channels or rays and I ultimately decided to have a local welding shop (locally called an engineering shop) make up a plate that would just cover the second course of floor firebrick with a hole aligned over the grate opening. We made some rather hasty measures and the plate came back in a timely manner but too wide. We made more hasty measures and the plate came back the correct width but still too long. Finally, on a third try with the friendly help of the remarkable mechanic neighbor, Lionel, we were able to get the extra length on the front cut off for a perfect fit. With the plate in place we were able to lay down a solid third course of firebrick on the plate guaranteeing that nothing could get into our channels or destabilize the floor. We assumed that the somewhat cooled firebox floor plate (incoming air) and the firebrick on top of it, would keep the metal from warping.

As we laid up the inner firebrick wall against the open channels we kept them clear at the top with little paper covers and reamed them out before capping them with a little sponge screwed to a stick. We did not fire the heater during the workshop, nor did stucco get put on the heater during the workshop, nor was a chimney for the brick to metal transition through the roof available or fabricated during our stay. This will all be documented and reported on in later stories. For the next New Zealand blog I will discuss the heat exchanger that we installed at the top of the heater and following that will describe the remarkable experience of acquiring and then milling on site several thousand pounds of soapstone that arrived in raw form and ended up on the heater sized, polished and fitted for all the trim that Sampsa has desired.

The photos accompanying this blog show the firebox design and construction process. When the heater is fully installed, the unit will be monitored and tested for efficiency and emissions and we will report those results to you as well. It feels to us that 2010 will be a year in which a lot of information on over fire air delivery systems and principles will be discussed and worked with. As with any product, there is always room for improvement and we are happy to keep doing our small part to push this design envelope.