Category Archives: Cordwood

Cordwood in Kenai, Alaska

This is Mark & Chelsea in front of their cordwood home in Kenai, Alaska.  The walls are 14″ spruce with foam insulation in the center cavity between the two 3″ mortar beads.

Here are more photos of their two story home.  They used a log wizard to craft the beams, posts and rafter.

Alaska provides ample solar time to work during the summer, but in the winter it can be a challenge.

Interior cordwood

Riding the wheelbarrow up to the second floor.

A final picture.   Nice job Chelsea and Mark.

Inspiration for future cold weather cordwooders.

Happy Trails,

Richard Flatau

Cordwood Construction Resources

Cordwood Hobbit Style House with round door and living roof in Wisconsin

Dan and Jessi P. built every hairy footed hobbit-fanciers dream home.  A 16 sided cordwood home (in Wisconsin,) complete with post and beam framework, living roof, masonry stove/heater/bake oven, stained concrete floor and a round, green hobbit door.

The work is artistic, attractive and very nicely done.  The bottle end  and cordwood walls are artistic, attractive and very well done.   The nasturiums on the floor add a touch of whimsy.

Here is a quote from Jessi’s blog.

“We’re proceeding apace with the walls, which look so lovely when they’re done – from a distance they look like stone. Labor intensive and messy, but beautiful. We also have the framework for the round green door done. So we’re looking hobbity!”

Jessi ends her emails with the following quote:

Not all who wander are lost.   J.R.R.Tolkien

Here is another quote from Jessi.

Subject: Cordwood House

Hi Richard – glad you like the looks of our place! All told, if you count the tree cutting/peeling summer, it took us about 5 years, but the actual cordwood stuff we squeezed into about two and half months – we started in October and laid up the last bit of wall the second week in December two years ago with the aid of much tarping and space heaters . It’s sixteen sided on a floating slab. The logs are 18 inches with loose fill insulation in the cavity. They are a mix of hemlock, spruce, and red pine which we took for the most part off the property. Our masonry heater was done by Gimme Shelter Construction over by you and then faced by a local mason, Wayne Kostka. Don was partially right in his comment – even on the coldest days this winter we were comfy with two fires a day, and it has stayed cool enough this summer that we haven’t bothered to move the window air con over from our old house. The roof is 6-8 inches of dirt over an Enkadrain drainage layer. Sedum we put in last fall has spread nicely and we put in another couple pounds of cuttings this summer, so in a few years when we’ve worn out the weeds it should be a nice low maintenance roof. All the rain we’ve had this year has given it a good test

To Jessi & Dan:

Kudos, congrats and thank you for sharing your wonderful cordwood home.

Richard Flatau

Cordwood Construction Building School

715-212-2870                715-536-3195

Firewood: Don’t Burn It, Build With It

This article by Clarke Snell was originally published in the New Life Journal.

Western North Carolina is becoming an incubator for green and natural building. As far as green building goes, homes built to Healthy Built Home standards have skyrocketed. We’re also well stocked with the latest cutting edge technologies and building concepts. For example though they were rare only five or ten years ago, you pretty much can’t shake a stick without hitting a hydronic in-floor heating system these days. Solar hot water is WAY back in, too, I’m happy to say. On the natural building side, it’s a real smorgasbord around here. We’ve got a number of code approved straw bale houses in several area counties. I know of two Earthships (a housing system that uses old tires packed with dirt as the wall system) in good old Madison County for god’s sake. We’ve got some cob, adobe, clay-slip straw, and the other earth/straw permutations around, too, though they seem to be more often built below the code radar than not. Conspicuously absent from our collection has been cordwood construction….until now. Toby Crawley and Maria Muscarella are nearing completion on a code approved cordwood house in Leicester. Let’s check it out.

What is Cordwood Construction?

Cordwood is firewood: air-dried, unmilled wood cut to length. Cordwood construction (often called “cordwood masonry”) is a technique for building walls with firewood. In the most basic approach, sticks of wood are placed in two beds of mortar separated by a space, usually several inches wide, which is then filled with some kind of loose insulation such as sawdust or vermiculite. (PHOTO). There are many possible mortar mixes. One popular mix contains sand, wet sawdust, lime, and Portland cement. Another uses lime and sand. Another paper pulp. Yet another simply clay, sand, and straw (cob). Cordwood walls can be designed to carry roof loads or they can be installed in combination with some form of post and beam structure. Since wood can shrink or swell, species and drying time are variables that are often debated by cordwood enthusiasts.

Cordwood Pros, Cons, and Performance

Pros: If you live in the forest, then the main advantage of cordwood is obvious: it’s an abundant, locally available, affordable building material. If you choose to go with a cob mortar and sawdust insulation, you could collect almost all of your wall volume from your building site. That’s saying something these days! In addition, laying cordwood requires only basic tools and simple skills. Once laid, cordwood walls require no additional finish such as drywall or wallpaper with sea shells on it. (Note: I’m only talking about the cordwood portion of the construction here. You still need a foundation, window and door framing, a roof system, heating and cooling strategies and systems, and all the other things that make a house a complex animal.)

Cons: Laying cordwood is a lot of hard, physical work. It also takes a lot of forethought in terms of cutting and drying the wood. (It’s a good idea to let cut and split wood air-dry under cover for at least a year before using in a wall.) In addition, the exposed end-grain of each piece of wood facing toward the exterior is susceptible to water infiltration and therefore mold, insects, and other damaging forces. Good design such as a proper foundation and good roof overhangs can go a long way to solving this issue. For me, perhaps the main functional cordwood con is wood shrinkage which can cause gaps and cracks that lead to air infiltration and even separation of cordwood from the mortar.

Performance: Comparing cordwood’s thermal performance to a more conventional wall system is difficult to generalize and beyond the scope of this column. However, I will say that since cordwood is made on site, it’s thermal performance can be adjusted to suit the specifics of the house project it is serving. The thicker the wall, the better it will resist the flow of heat, so you can theoretically generate the performance you need by adjusting wall thickness. In colder climates, an option for increasing thermal performance is double wall cordwood masonry, a system employing two cordwood walls separated by a space filled with insulation. Wood is both a decent insulator and a good thermal mass, so it is competent at both resisting heat flow and holding heat. Another potential performance plus for cordwood is it’s hygroscopic nature…it’s ability to take on and give off water vapor in response to changes in humidity levels. This trait theoretically helps wood to balance indoor humidity levels and therefore potentially improve indoor air quality.

Toby and Maria’s House

As someone who has been hangin’ around the natural building water cooler for a number of years, I have to say that I’m always skeptical when I hear about the next wave of novice owner builders taking a shot at home construction. Sometimes it works out great and sometimes…well it’s a disaster. I’m happy to report that Toby and Maria are doing a good job and look like they are going to make it through intact. In my opinion, their secret to success has been (1) an initially somewhat realistic budget and (2) the financial flexibility to go well over their initially somewhat realistic budget.

After doing their research and checking out a variety of options, Toby and Maria chose cordwood over other “natural” building options because they thought they could muster the skills and reasoned that cordwood could pass code in the area. This turned out to be true probably mainly because they chose a post and beam structure with cordwood infill. The post and beam construction was stamped by a structural engineer leaving the cordwood infill with no official structural role. They cut cordwood from poplar harvested on their property and bought most of the rest of the framing lumber from a local mill. They salvaged hardwood floor from a dumpster (it looks great!) and bought most of their doors and windows from Habitat for Humanity.

The approximately 1,400 square foot building is 16-sided and roughly circular. It will have a living roof planted with sedums. The north section of the first floor and the small second floor are wood framed and insulated with Icynene spray foam leaving roughly the east, south, and west areas of the first floor in cordwood. Though they are hooked up to and existing well and septic system and have a flush toilet, Toby, Maria and family plan to continue using their sawdust toilet and composting their humanure for use in the garden. (Yeah, baby! See my rant against flush toilets in other of my writings or just stop me on the street to get an earful.) They have hydronic in-floor heating fed only by solar collectors, i.e. there is no boiler back-up and therefore no petroleum based fuel input. The back-up heat source is a high efficiency wood stove. Last, but not least, they are using Earthpaint finishes throughout the building. (If you don’t know about local paint and finish manufacturer, Earthpaint, get with it already!)

If you want more information, Toby and Maria have graciously agreed to supply a contact email address ( They still have some cordwood to lay, so get in on the next cordwood party! As for me, I’m always looking to deepen my knowledge of the local natural and extreme green building scene, so don’t hesitate to send me leads and contact info for interesting projects at Until next month, keep it green.

Cordwood Education Center on the cover of Backhome Magazine Jan/Feb 2010

There is a fine photo of a team of Percheron’s pulling a sleigh on February 14, 2009 in northern Wisconsin on the cover of Backhome Magazine (which is published in Hendersonville, NC.)

The Cordwood Education Center in Merrill, WI
The Cordwood Education Center in Merrill, WI

There is a 3 page article entitled Community Constructed Cordwood which details the volunteer labor used to build and then donate this 850 sq. ft. building to the local school system. The cordwood building is constructed using Best Practices and Energy Star Guidelines.  There is more information at

To read the complete article go to:

A recycled bottle end (stained glass) wall at the Cordwood Center.
A recycled bottle end (stained glass) wall at the Cordwood Center.

Richard Flatau

Cordwood Construction Resources

Merrill, WI

Cordwood Bookstore link

White Earth Reservation Cordwood home

Built by Bill Paulson
Cordwood Bear Paw for Native American owner

In the spring of 2008 the Midwest Minnesota Community Development Corporation made contact, to inquire as to the possibility of building a cordwood home on the White Earth Reservation in NW Minnesota (50 miles east of Fargo, ND). The original idea was to build a daycare and early childhood center and a home, but, for various reasons the home came first.

Anishinaabeg Cordwood Crew 09
Anishinaabeg Cordwood Crew

After many, many months of consultation and conversation, we were on our way to Naytahwaush to begin construction on September 22, 2009. The General Contractor, Robert Zahorski of Clearwater Building and Design was ready with the foundation (radiant in floor heat in a sand bed, using off peak electric hours—3 cents a KW); post and beam cedar frame, 12/12 pitch roof with 2 large bedrooms and a half bath and storage (shingled), a well, a mortar mixer, mortaring supplies and power!) What a great guy to juggle all these parts of the project.
The Native American Group Leader Bill, had been working to gather a cordwood masonry crew. Bill is a very talented individual with a skill set that defies description. Needless to say, he and Robert became our confidants and close friends. We are grateful for time we shared with them and the crew. The staff at MMCDC was most excellent in providing everything needed to make this a success.

1700 sq. ft. cordwood home in Naytahwaush, MN
1700 sq. ft. cordwood home in Naytahwaush, MN

There is a link that explains more about the home and the project. The plan is to build 5 more next summer.   There was an interview about the cordwood home on Minnesota Public radio.  That link is at the bottom of the first link.    Give a look-back at the daycreek link (above) as the building progresses.  There is a bottle end medicine wheel built into the wall and a feather in addition to the bear paw.

Richard & Becky Flatau
Cordwood Construction Resources LLC
W4837 Schulz Spur Dr
Merrill, WI 54452

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Cordwood Maintenance

This posting concerns Cordwood Maintenance, specifically about log loosening.  Air infltration is not a good thing to have in a cordwood home (or any home for that matter), but sometimes a log loosens in the wall.  There is a most excellent remedy for log loosening out there in ‘log home land.’   Permachink (and Log Jam) are water based, acrylic co-polymers that are easily applied to the mortar and wood.  They are elastic and  move with the log ends as the seasons change.  Orignally designed to be used for chinking on horizontal log cabins, Permachink and log Jam work wonders to eliminate air infiltration in a cordwood home.  See and for further information on their products.

This posting is taken from the most wonderful blogsite My Amazing House by Maria & Toby There is a co-joined blog site about all things herbal and home by Maria called Dirt Under My Nails Both are very good reads.   Positive, earth affirming and energetic.

Here is their latest post.

September 9th, 2009
This weekend we got started on the project we’ve been dreading for the last year… winterizing the house. With a cordwood house, there is a lot of shrinking in the wood that goes on the first year. So, after the first winter, you need to go back and seal the nooks and crannies that have opened up. We weren’t looking forward to this large amount of detail work.

Well, I’m happy to say that it’s not nearly as bad as we thought it would be!

We purchased some Permachink (a sealant often used on log homes) from a dealer not too far from us. It comes in huge tubes that you squeeze onto the wall. Toby would squeeze the ‘caulk’ around each log end and I would go behind him and smooth it out. The color is an exact match to the white of our walls… unfortunately, the lower part of the exterior walls has some red mud splash back from the rain… so the caulk really stands out here. I figure I’ll get Kaia to go splash in puddles near the house next time it rains and that caulk should be nice and dirty in no time

permachink on left, none on right

Smoothing it out

We were able to do almost 2 sections (out of eight) this past weekend (with many interruptions!) So, we will hopefully be able to finish this in a few weekends. Then, it’s on to the chicken coop!

Thank you Maria & Toby.

Richard Flatau
Cordwood Construction Resources, LLC
W4837 Schulz Spur Dr
Merrill, WI 54452

Cordwood Bookstore

Cordwood Workshop

Taking a cordwood workshop is one of the best ways to learn the ins & outs of cordwood masonry construction. Valuable information is passed on, questions and answer sessions are important to cement down cordwood concepts and the hands on portion becomes the bread and butter of how to build a cordwood building.

The host & family with timber frame mallet
The host & family with timber frame mallet

The interaction between attendees is not to be overlooked. At our last workshop we had a doctor, lawyer, judge, police officer, vet, pianist, three general contractors, three teachers, a factory worker, a biker and a host of homemakers. The give and take was amazing. Friendships were formed and a cordwood blog group was organized to help keep in touch.
Here is a link to the workshop in Custer, WI. The project was the cordwood infill of a Colonial Hall & Parlor style timberframe which was modeled after the first timberframe home in the US. The cordwood infill was 17″ northern white cedar with a Lime Putty Mortar mix. Lime Putty Mortar uses only sand and Type S builders lime which has been hydrated for 5 days. Similar to how the good ol Roman’s built their buildings.
We will be teaching a cordwood workshop in Hendersonville, NC on Oct. 10-11, 2009 at the home of the editor of Backhome Magazine. The project will be the 18″ cordwood infilling of a post and beam frame greenhouse. The link to the registration form is at,%20NC%202009.pdf
Richard Flatau
Cordwood Construction Resources, LLC
W4837 Schulz Spur Dr
Merrill, WI 54452

Cordwood Information and books

The Colonial Hall & Parlor Timber Frame using Tamarack & Pine
The Colonial Hall & Parlor Timber Frame using 18 ' Tamarack & Pine
The diverse and intelligent crew at the Custer, WI Cordwood Workshop in August 2009
The diverse and intelligent crew at the Custer, WI Cordwood Workshop in August 2009
Timber frame with stackwall corners using lime putty mortar & cedar
Timber frame with stackwall corners using lime putty mortar & cedar. Anne takes a break after a hard days cordwooding.

Cordwood Information and books

Cordwood House Plans on

One of my favorite websites for information on Cordwood Construction is not only has cordwood photos, literature and articles on cordwood from major magazines, but it also has a Forum to share and  ask & answer questions.
Recently a couple from St. Cloud, Minnesota posted some drawings and pictures of a state of the art cordwood home they are building.
If you are interested, check it out at the following link.

Happy Trails,
Richard Flatau
Cordwood Construction Resources
W4837 Schulz Spur Dr
Merrill, WI 54452

Cordwood Information and books

Cordwood Construction in the Upper Peninsula of Michigan

My wife and I had the pleasure to spend four days in the Keweenaw Peninsula of Michigan.  This is the area near Houghton/Hancock and is on the way to Copper Harbor, Michigan.

Chain saw carving bench and cordwood wall
Chain saw carving bench and cordwood wall
Camp Cordwood near Lake Linden, MI
Camp Cordwood near Lake Linden, MI

We stayed at the home of long time cordwood builder Wayne Higgins.   He took us around to a number of fine cordwod buildings and introduced us to the owners.   We also undertook to help and learn on a cordwood building site that was using Lime Putty Mortar.   More information on Lime Putty Mortar’s use in cordwood construction in a future post.

Two story cordwood with large round pine logs
Two story cordwood with large round pine logs

My purpose in writing here is simply to publish a few pictures of the cordwood we saw as a kind of cordwood eye candy posting.

Bathroom bottle ends and shells
Bathroom bottle ends and shells

I hope you enjoyed the images.

Richard Flatau  Cordwood Construction Resources

Merrill, WI  54452 
Cordwood Information and books

Best Practices: Cordwood Construction

My friend, the author and cordwood expert Richard Flatuau, was nice enough to write this excellent short article on cordwood for the digital update to “Building Green”. He promises to blog here on occasion, so check back for more good cordwood information.

Best Practices with Cordwood Construction
By Richard Flatau

Over the years the people in the cordwood field who have kept building, writing and helping have come to realize that there are several techniques that can be considered Best Practices to use with Cordwood Construction.
Like all building decisions there are continual cost/benefit/budget decisions that must be made before and during the construction of your home. There is no absolute right way to build your home, rather there are decisions that you must make based upon available money, skills, time, talent and preferences. When we built, one of our main goals was to come away from the project mortgage-free. Not everyone has that goal and so you adjust your purchases to meet your goals. For example, rather than buy expensive cabinets, we ordered birch cabinets from the former JC Penny catalog for 1/5th of the cost of regular cabinets in order to meet our goal. We didn’t scrimp and save on the safety aspects: wiring, plumbing, chimney, furnace, windows, but we did make monetary concessions on the plumbing fixtures, floor coverings, cabinets, etc. You too, will have to make decisions based on your goals and objectives. Take the following discussion on Best Practices with that in mind.

1. Foundations: Most cordwood builders use an insulated frost protected shallow foundation (FPSF). Others are implementing Frank Lloyd Wright’s rubble trench foundation as an alternative to costly foundation work. Several are putting radiant-in-floor heat into the slab. It is, of course, possible to build cordwood with a basement or crawl space, and this adds to the cost of the building. If you prefer a basement and have that as a goal, put in a basement. Remember that even with an insulated slab you can frame out the floor and put in hardwood floors. Some cordwood builders have done this and used the 2” x 6” floor framing to run electrical, plumbing and heating.RF_cordwood1

2. Post and Beam: Most cordwood experts now agree that one of the advantages of post and beam framing is that you can put your roof on first. That allows you to do the cordwood masonry ‘out of the elements’, it also gives you a covered space to store all of your log-ends, tools and supplies. It affords the opportunity to build one section of wall at a time. If winter comes early, simply side up the sections that aren’t finished and finish them in the spring. Even folks who have chosen the stackwall corner are beginning to post and beam the walls in between the stackwall corners.

This handsome couple is rightfully proud of their post & beam framed, cordwood garage. This was their “practice building.” They learned the cordwood technique and came away with a 2½ car garage with “upper” living quarters.

3. Build a Practice Building: In order to find out if the alternative building technique you are enamored with is the “right fit” why not build a small (doghouse size) or large (garage) practice building. This way the system is researched, tested and evaluated. It can be an effective method of learning and deciding. Or you can do like Clarke and build a cottage using multiple systems.

4. Mortar Mix: The mortar mix must be one that will cure slowly and set up relatively slowly. There are about four basic mixes. Some will leave your walls smooth and others will have an adobe type quality. Before you make a decision it is wise to try a few of the mixes and see what they look and feel like before and AFTER you mortar. It is also good to see which ones crack more and which retain their color. The latest craze in cordwood is a Lime Putty Mortar (LPM) mix which is basically how the Romans did it. Type S hydrated lime, soaked for three days, mixed with mason’s sand in 2.5 sand to 1 LPM ratio. I will write an article and give all the gory details on how to use this new/old mix. Soaked sawdust and slurried paper have been used successfully to slow the set and cure of the mortar.

5. Wood Prep & Drying: The biggest problem with cordwood is the natural tendency of the mortar to separate from the wood. This is why it is so very important to dry wood to the minimum moisture content for your area. Here in Wisconsin that is 12% for air-dried wood. Your wood should have cracks and checks in it before you use it. Otherwise it will shrink in the wall and let air in. Borrow a moisture meter from a lumber yard, sawmill or a friend. Or buy one. Burn a piece of your wood and see if it spits and pops (if it does, it is still too wet.)

6. Split some of your wood. If you want your wood to dry faster, try splitting it. Splitting makes two things happen. The wood will dry faster and there will be no primary check to allow air infiltration.

7. Perma Chink & Log Jam: NO matter how dry your wood is, there will still be some pieces that loosen up or check. This is a cosmetic problem and can easily be solved by putting (slathering) PermaChink or Log Jam caulk on the mortar and the space where the log end and the mortar meet. In fact I was just in a house that had ALL the mortar PermaChinked. Believe me there was no air infiltration in that home.

8. Cedar and other softwood: Cedar is the ideal wood for cordwood. It is light, has a good
R-value, is naturally decay resistant and has a light attractive end grain. However, except for staying away from hardwoods (they have a tendency to swell and crack mortar joints) most of the other dry, insect free softwoods are suitable for cordwood building.

9. “Treat” the wood to a borate bath: It is becoming common practice to spray or soak the cordwood in a solution of borate (borax). The most preferred, economical method is to use 4 cups of 20 Mule Team Borax (borate) with a gallon of hot water. This can be sprayed on, or the logs can be dunked. This treated is a “three-fer:” an insecticide, a wood preservative and a fungicide. Commercially available products can be used: (Timbor, Shell-Guard, Pentatreat, etc.)

RF_cordwood310. Large Overhangs & gutters: In order to keep the cordwood dry and free from splashback, it is a good idea to have at least a 24” overhang. It is also a good idea to gutter your roof eaves to prevent against splashback.

11. Build up off the ground: Most experienced cordwood builders recommend that you start your cordwood at least 12 inches off the ground, however, if your climate is especially prone to high water or straight-line rain, and then you will want to consult with local officials and apply what works for your locale. We have been using split faced block on the outside and inside with an extruded polystyrene thermal break in-between.

12. Code Compliance: One of the main thrusts of the Cordwood Conference 2005 was to establish a document that dealt with Code Issues. Fortunately the document
Cordwood & the Code: A Building Permit Guide was one of the gems produced by the Conference. It comes in a 54 page volume with an attached CD that will allow most owner builders to approach the code officials with confidence and success.

13. Build small now, add-on later: Some would advise building a smaller structure now, while leaving room to add on later as more resources become available. This is one of those areas that become a personal decision, but it is important to know that it is an available option.

14. Random Pattern: Don’t build with all one size wood, use a random pattern to give your cordwood building an attractive appearance. Step back from the wall every so often to see what you are building.

15. Use Energy Startm Guidelines:
• Energy Heel Trusses that allow R-60 in the ceiling and especially at the point where the top plate meets the truss.
• Energy Efficient Windows and doors. Much of the heat loss in a home comes from leaky windows and doors.
• Standing Seam metal roofs are long lasting; provide some fire protection and let snow and tree leaves/needles slide right off.
• Living Roofs are an important consideration and should be thoroughly researched if chosen as an option.
• Seal all electrical outlets
• Caulk all inlets and outlets (plumbing, electrical, etc) to keep the home as air tight as possible.

Beautiful random patterning with unique wood features in Haida Gawaii, BC, Canada.

Richard Flatau
Cordwood Construction Resources
W4837 Schulz Spur Dr
Merrill, WI 54452