Firespeaking

Masonry Heaters, Wood-Fired Ovens, Natural Building

Masonry Heater in Bend, OR

allen-heater

Masonry heaters are a relatively new tradition in North America. We do not have the same tactile memory that many Europeans do of experiencing the warm, thorough heat. As such, many of us builders spend a lot of time educating potential clients. This was not the case with the Allens!

This was their fourth masonry heater in as many homes! They knew exactly what they wanted and knew all of the benefits of living with a masonry heater from their many years of experience with them. Their first heater was a “Russian” heater and their second two were built from Tempcast kits. Although satisfied with the Tempcasts they had, they hired us because they were interested in the Masonry Heater Association’s 5-run design due to its compact footprint and top-venting chimney.

Process….

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Custom Masonry Heater at Abundant Solar (Corvallis, OR)

(click on images to enlarge, hover over for descriptions)

the beginning

stainless steel hot water pipes carved into replaceable firebox liner

oven/core detail

site

layout for the jack arch

dylan boye tooling joints

flue liner detail

(process photos by Dylan Boye)

Have you ever heard of Earthships?  The term refers to a grouping of design principles that aims to make houses as self-sufficient as possible.  They were pioneered by a man named Michael Reynolds, a creative architect genius from New Mexico, who wanted to move away from homes being consumer boxes that demand resources like water and electricity from a grid and require connections to such things as septic dumps and trash collection.  Instead, he made concepts such as rain-water harvesting and storage, grey water treatment, micro-power generation and extreme passive solar design for heating and cooling shape the form and function of “earthship” homes.  The specifics of his design principles are honed for the climate of the southwest which includes very cold but sunny winter days and a scarcity of water.  I have always felt it an interesting challenge to understand how we might apply these same principles to other climates.  In the Pacific Northwest where we live, for example, the sun rarely shines in the winter time but the forests that abound are extreme accumulators for the solar energy that shines during the rest of the year.  As we worked on this project, influenced by the clients’ affinity for earthship design and a shared interest in applying these ideas to our bioregion and our lifestyles, I came to see the masonry heater we were building both as this vessel’s navigation deck from which they will be able to stay warm and steer through the colder parts of the year.

This masonry heater was built at the home of James Reismiller (owner of Abundant Solar) and Cassandra Robertson (environmental engineer and excellent singer-songwriter).  They did a great job of researching and planning for this heater.  The outside air source and reinforced foundation had already been installed before we were brought on.  In fact, the house was pretty much completed except for this central element.  They wanted a heater that would flow with their modern clean lines and be consistent with an ecological way of building.  They wanted to heat water, they wanted an all-season bake oven, and they wanted a configuration of heated benches that would flow well with their stairs as sitting space for house concerts.  So…. we got to work and designed and built the heater.

It is based on the Contraflow with the 22″ replaceable firebox from the Masonry Heater Association Plan Portfolio.  The interesting design challenge was to both provide for the heated benches as well as preserve access to the ash box, especially while needing to meet the low height of the second stair which meant that the bench’s flue could not cross above the access to the ash drawer.  The utility room which houses their hot water tanks for distributed radiant floor heating and domestic hot water is directly the other side of the back wall so the natural thermosiphon loop for the hot water was very simple and straight forward.  The bricks we used for the facing were very dense recycled pavers that beautifully reveal the flame patterns of the kiln they were fired in.  The bench and trim details are soapstone that were cut and polished on site from slabs that were seconds at a counter top shop.

Stay tuned for photos with fire as well as possibly a stop-motion video of the process!

This heater begs to make gracious acknowledgment to the following:

  • Cassandra and James for the opportunity to participate in their home’s construction and their hospitality.
  • Dylan Boye for his hard work, precision in cutting, and general assistance.
  • Kiko Denzer for his assistance especially in laying out and cutting the soapstone
  • Eva for coming at the end and helping to finish up and giving it her special pretty touch.
  • Marcus Flynn of Pyromasse for his generous documentation, tutorials and correspondence.  See this great tutorial on how-to-build a jack arch.
  • Norbert Senf of Masonry Stove Builders and Steve Bushway of Deerhill Masonry for their readiness to offer advice especially in the design stage… and to the whole MHAMembers chat list for great discussion which contributed enormously at various points in the build.

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Ledge Stone Masonry Heater Near Eugene, Oregon

This heater was built for a family who live near Eugene, OR.  It features a see-through firebox, heated bench and a bake oven.  The outside skin is laid with Montana Bitterroot ledge stone with Three Rivers stone detailing the bake oven arch.  We cast, poured and and polished the bench which includes special embedded stones and fossils.

The heater has a compact, responsive design which serves as a partial wall between living and dining room spaces.  It could have many different facing looks, occupies an area of 48″ x 48″ and stands 6 1/2′ tall.

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Thanks to Greenleaf Design Build for their good organization and excellent
craftsmanship which allowed our work to flow together seamlessly with their’s.

Masonry Heater at the Allen’s (Portland, OR)

 

We built this masonry heater in the Portland area in autumn of 2011.  Our clients had collected many beautiful bricks dating back to 1883 (a long time from our West Coast perspective!), local basalt rock, and cobble stones that originally paved the streets of Portland.

This masonry heater (based on the Swedish 5-run design) has a see through firebox, a bake oven, a three-sided heated bench, and a place for wood storage.

This project brings together our understanding of the technical aspects of combustion and heating efficiency and our experience with design and use of recycled building materials.  The heater is currently curing and the exit flue will be installed shortly.  We plan to update this post once the heater is fired and make new posts about the process of this build and about the use of polished “concrete counter tops” for benches and other elements of mass heaters.  Check back on this site, join our mailing list, and see more about this project on Facebook.

Thank you to Norbert Senf and Doug Hargrave for their development of the Norccore and for generous technical assistance in preparation for this project.  Thank you also to Jerry Frisch for continual support and inspiration.

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The Cabin Stove – A Small Masonry Heater at Aprovecho Research Center

A good part of the month of August has been dedicated to the research, development and construction of a small multi-functional masonry heater I have been calling “The Cabin Stove”.  Eva and I have both been working as instructors in the first year of the Sustainable Shelter Workshop Series at Aprovecho Research Center in Cottage Grove, OR.  The building that is the focal point for this course has been designed to be just slightly smaller than the legal requirements for permitting so that it can at the same time be a teaching tool as well as a laboratory for a basic building system that a group of associated natural builders in the Pacific Northwest considers to be a sound and ecological way of making a home.

The challenge of the design of the Cabin Stove was to come up with something that was very compact but also still resembled and functioned like a masonry heater.  The design criteria included heating the small space, an efficient and clean fire, utility for cooking, heating water, combining some quick/immediate-releaseheat with slower retained radiated heat, relative ease of construction, not too expensive, aesthetically pleasing, and being as compact in size as possible.  A very interesting process to try to combine all of these together.

Our test firings of the prototype in our shop were very promising.  The fire burned well and had no problem making its way through the longer pathway, even notably when the door was open with the beautiful cast fire screen reducing the overall air intake to a moderate amount. I think the design meets most of the criteria listed above well with the exception possibly of cooking utility since this was compromised to accommodate other features.

For the initiated, it is basically a very compact J-loop contraflow with a bi-pass that runs directly to the flu and allows it to function even as an open fireplace.  Rather than insulating the top of the heater as is done often in masonry heater construction, there is a 1/4″ steel plate placed on top that serves as a cooktop and source of immediate heat.  I am optimistic that the proportion of immediate and retained heat will be a good one for our bio-region where temperatures can fluctuate greatly during the day and from one day to the next.  We are within but on the outer limits of the kind of climate that masonry heaters were designed for which explains the need for continued development and innovation.

I did notice in firing the prototype that the big steel plate I had placed on it arced noticeably when hot so I welded a 3/16″ frame onto the Cabin Stove we built at Aprovecho though I am quite sure that the heat will play its funny games and have its own way with the final shape of the steel plate.  Cast iron is almost certainly the way to go for the top although I do not know of a source of affordable custom sizes.

Although the heater at Aprovecho was designed to be a double-skinned heater with a compressed earth block and local stone veneer, I am very excited that we will first test the heater with a single skin.  A neighbor has offered to lend his carbon-monoxide and air-quality monitors to test whether there are any dangers that result from expansion cracks in the single skin.  Given our climate in Oregon, the prospect of building responsive single skin heaters is a very interesting one.  (Note: the variation in the firebrick is because we used firebrick out of an old heater that had been taken down.  The students re-milled each brick to cut away the old mortar to return the brick close to original dimensions).

I have recently been very inspired by the Open Source design philosophy so I share the rest of these photos of process in that spirit!  Stay tuned for more on this heater and other research and endeavors.  Click to see any images enlarged.

You can see some other details of the building, including one of the timber frame’s posts; the faswall and stone stemwall; and strawclay insulation packed in between Larsen-truss style framing.


Custom-made heater hardware, made in our shop from scratch.

Details of Hot Water Serpentine.  More on Plumbing for Thermosiphoned Hot Water Systems….

The light and surrounding forest were really exquisite when I took these shots of the veneer material.  The compressed earth blocks were made by the students.

Find out more…..

Cob Masonry Heater at Cob Cottage Company

cob masonry heater group

This is a very exciting and experimental masonry heater built by many hands through a workshop at the Cob Cottage Company in southwestern Oregon.  The challenge – that Ianto Evans is so consistently a champion of – was to build a masonry heater that was made of local materials and through local craftsmanship.  Flemming Abrahamsson, master mason and incredible human being, traveled from Denmark to guide us in the work based on his decades of experience as a heater builder in Europe.  The inside of the heater is based on a Swedish 5-run design.  It is a single-skinned heater which has a firebrick core and is faced with recycled brick set in a clay-based mortar from clay dug on site and cob.  The hardware for the heater was fabricated by Max – his first arched glass door!
The plaster and paint were made and applied during a class taught by Eva Edleson and Jo Forsyth during the Complete Cob Course.

Jon Santiago, one of the participants in the course, documented the build wonderfully in this Facebook album.  For those interested in how it was built, it is worth zooming in on each photo.

Join our mailing list for updates about it how it fires and performance through the winter.

Further reading…..

Corner Heater

Handmade Earthen Plaster and Raku Tiles

Imagine a wood stove that you only had to fire for two and a half hours in the evening and that the heat produced would keep you warm all through the next day.  Imagine you could bake in it and heat your domestic water.  And imagine that all of that functionality fit beautifully into one corner of your living room!  We are excited about our most recent project, a corner masonry heater.

Amongst the many benefits of masonry heaters, this project rekindled our interest in combining solar heated hot water in the summer with wood heated hot water in the winter.  Perfect complements.  We installed a heat coil in the fire box of this corner heater. (More on plumbing for masonry heaters.)

The water heated in the coil naturally travels upward into the hot water tank and is replaced by colder water coming down from the tank in a process called thermosiphoning which does not require any pumps.  Stay tuned for more information on heating hot water and photo updates of Walt and Marion’s corner heater in northern California.


Masonry Heater at the Rainwater’s

This masonry heater has a simple compact design and includes a bake oven. The technical core is built with firebrick and the heat receiving outer shell is made of compressed earth blocks. Natural ledge stone was used at the base, an earthen plaster was applied as a finish and we installed tiles that were meaningful gifts to the homeowners.  This heater represents a good example of Firespeaking’s ethic: providing warmth and function while using locally harvested materials and completing the project within an affordable budget.

New heaters in the world – a summer update!

This summer has been an exciting time to deepen our craft in masonry heater building.

Here, Jerry Frisch of Lopez Quarries and I are standing in front of a heater that I assisted him on in a new house on the Puget Sound in the state of Washington.  It is a basic Finnish contraflow design which includes a bake oven and a heated bench on two sides.  Other masons from the Masonry Heater Association also came to help out on the heater as the whole effort was part of a  fundraising effort to raise funds for the MHA in order to be able to do lab testing on stoves to prove empirically to the EPA how clean-burning and efficient masonry heaters are as they draft new regulations for wood-burning appliances due out in a year or two.  A more in depth story will follow…

And here is an interesting project that Kiko Denzer and I just completed:

This was an interesting project that involved modifying an existing solidly-built woodstove into a masonry encasing in order to extend its flue path and create mass that would absorb more completely the heat from the wood burned.  It has a “bi-pass” damper, which acts as a valve, and allows one to heat up the flue directly.  When this damper is closed, the gases then follow a different route: back down, through the bench, and then up to where it re-unites with the original flue.  There is another damper called a shut-off damper which is used when the fire has burned out completely to shut the flue system completely and hold in all the amassed heat.

Construction shot showing flue liners in bench:

This project also represents a breakthrough for us in being able to do computer-aided design to conceive of and plan a project.

This is simply an update….  we will post much more thorough posts about each project when the dust from the summer has settled!  ‘Till then!…..

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