Cordwood building in zone 4 and colder?

Hi there. I am researching natural building and noticed cordwood. Has anyone built a home with it? Or even a garden shed? Just wondering how insulative it is for my area (northern midwest, USA). My guess it is not very warm. Probably the warmest would be straw bale. What do you think??

Richard Flatau is a well known cordwood builder in central WI which is zone 4.  There's a hundred year old two story cordwood building several towns away but I've never seen it in person.  And a guy I know near me lives in an octagon shaped cordwood house.  So it has been done plenty in zone 4

I think the R value is pretty good with a gigantic "IF" attached to it.

The wood itself has a R value in the low 1 range (1.0-1.4 I believe).  But if the wall is 18" thick, that gives you a R18 to R25 which is really good.

The huge IF is the mortar joints.  If the wood swells or, more likely, shrinks you have gaps that leak air like a sieve.  Richard's books likely have good recipes and techniques to mitigate this.

You might be limited regarding building codes but I'm not sure.  Probably no worse than for straw bale.  I'd be tempted to go with whichever material is more local to your spot.  If your northern Midwest location is North Dakota, straw bale would be the one.  If you're talking Michigan, then wood.  But that's just my thought process :)

Mike Haasl wrote:Richard Flatau is a well known cordwood builder in central WI which is zone 4.  There's a hundred year old two story cordwood building several towns away but I've never seen it in person.  And a guy I know near me lives in an octagon shaped cordwood house.  So it has been done plenty in zone 4

I think the R value is pretty good with a gigantic "IF" attached to it.

The wood itself has a R value in the low 1 range (1.0-1.4 I believe).  But if the wall is 18" thick, that gives you a R18 to R25 which is really good.

The huge IF is the mortar joints.  If the wood swells or, more likely, shrinks you have gaps that leak air like a sieve.  Richard's books likely have good recipes and techniques to mitigate this.

You might be limited regarding building codes but I'm not sure.  Probably no worse than for straw bale.  I'd be tempted to go with whichever material is more local to your spot.  If your northern Midwest location is North Dakota, straw bale would be the one.  If you're talking Michigan, then wood.  But that's just my thought process :)

Thanks. I am in Wisconsin actually. Just doing research though. Probably for fun. I don't see this method being permitted to live in where I am. I know people have built sheds and barns using it, but not sure about home to live in.

Yeah, I love the technique.  I'm not sure if there are parts of the state where you could do it for a dwelling?  Richard would know...

Hello Mari & Mike,  Yes, we have 23 cordwood buildings in Lincoln County (Zone 3) and the last 3 were code approved single-family homes.  We put together a booklet called Cordwood and the Code: A Building Permit Guide that shows all the latest test data on cordwood homes (R-value, moisture movement, compression strength, blower door tests, best practices, etc.) and 2 approved permits in Wisconsin and Minnesota.  In Wisconsin, if a building is approved in one county the other 71 counties have to take a fair look at it (Uniform Dwelling Code).   The link to find more information is at https://cordwoodconstruction.org/ and we also have an excellent FB Group page for asking and answering questions.  https://www.facebook.com/groups/cordwoodconstruction
All the best to you in your research.   Richard Flatau Director  Cordwood Construction Resources