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Cordwood Masonry is great for DIY builders but requires knowledge and practice to do successfully. Here we’ll provide you the valuable resources we used to get our building off the ground and show you some tricks we learned along the way.
What is Cordwood Masonry?
Cordwood Masonry is where logs are cut to the same desired length and laid with the grain facing out instead of running lengthwise like traditional log homes. Logs lay in a bed of mortar with insulation in the middle.
How is this different from standard log construction?
In standard log construction, the side grain runs to the outside. In cordwood construction, the end grain is exposed instead. For example:
What are the basic building blocks of a cordwood wall?
LOGS: Trees are cut down, peeled, and cut to uniform lengths to match your desired wall thickness (ours are 16″). Ideal logs come from softwood trees, though hardwood can be used if it is the only thing available.
INSULATION: Typical insulation for cordwood masonry is sawdust mixed with dry masonry lime. The lime prevents decay/pests and using a softwood sawdust (typically cedar, though any softwood will do) provides an effective and green insulation.
MORTAR: There are several mortar mix recipes out there. It can be made with Portland cement, but we chose to make ours out of LIME PUTTY instead to keep it simple.
Our mortar recipe is simply 2.5 parts sand : 1 part hydrated type-S masonry lime.
Why We Chose Lime Putty Mortar
Lime putty has three advantages for us:
- The mix recipe is simple.
- It can “self heal” small cracks while Portland mix cannot.
- It takes much longer to set, which allows us more time to smooth (aka “point”) the mortar and fix any mistakes in the wall. This is good for those days when our schedule doesn’t allow us time to point right away. Even on hot, dry days we can come back the next morning and still be able to point and smooth the mortar without problems.
- The mortar is a brighter, whiter color than a Portland mix, which is more grayish.
You can learn all about mortar here!
Logs in mortar? Won’t it rot?
No! By its very nature cordwood masonry is rot resistant. See this very detailed post about how to prevent rot from happening in a cordwood wall.
[Very] Basic Steps to Building a Wall
- Run two lines of mortar along the edges of your wall.
- Fill in the middle with your insulation.
- Place logs on top of the lines of mortar.
- Run more mortar along the tops of the new logs and fill the middle with more insulation.
- Rinse and repeat until you reach the top.
- As the mortar dries, smooth the lumps out with a smooth knife.
Your needs may vary, but you’ll get the most mileage out of having:
- A good wheelbarrow
- Shovels and/or scoops (for mixing and measuring ingredients for mortar and insulation)
- Lots of buckets (for mixing, storing, and distributing lime, sawdust, etc.)
- Non-toothed knives that have been bent at the end for pointing/smoothing the mortar (like a butter knife or spreader – we got ours at an antique mall)
- Wood scraper (for cleaning the ends of the logs – we have two of the ones pictured below)
- Soap, sponges/scrubbies, and access to water for washing hands and tools
Nice to Have
These are more “luxury” than requirements, but we have found that for us to save time (especially in the run up to school starting) these have been a Godsend:
A concrete mixer – most cordwood experts will tell you that you don’t need one, and it’s true, you don’t! We mixed the first panel’s worth of mortar by hand with a garden hoe in our wheelbarrow…and it took forever. So long, that it took three days just to complete the panel. Maybe it was our inexperience, maybe it was our impatience…whatever it was, it worked best for us to plunk down some cash on a mixer similar to this one. It’s an electric mixer, so we run it with our generator. We can be working with one batch of mortar while mixing another one so we can keep the wall going continuously.
Metal Pans – This is the biggest thing along with the mixer that has sped us up immensely when setting mortar. The idea is to load up your pan with mortar so that you can quickly and easily grab handfuls to lay on the logs without having to constantly go back and forth to the wheelbarrow.
We’re using paint trays since they are what we had access to, but cake pans were what Mark was originally after.Especially when we were at the top of the wall, we’d have to grab some mortar, climb the ladder, set the mortar, climb back down, go back to the wheelbarrow, grab another handful, etc. etc.
Having mortar with me in a pan means I can grab and go. Even if the wheelbarrow is only a couple of feet away…do yourself a favor and use a pan. Even a sturdy bowl could work!
Tips and Tricks for First-Time Cordwood Builders
Tip 1: Go to a workshop!
Last year, Mark got a chance to go to Rob and Jaki Roy’s cordwood masonry workshop to learn the finer points of cordwood building from true experts. If you have an opportunity to go or can save up, it’s worth the investment. If he and I were just going off of what we had read, we’d probably still be out on the property fighting over how to start the first course of logs! Nothing beats getting real life advice from seasoned experts while working on an actual project.
I’m still pretty sad that I couldn’t go, but the school where I teach had graduation that weekend, so Mark took lots of notes and pictures for me. He got a chance to really get his hands dirty and learn the finer points of building with cordwood, but what about me? Until now, I’ve only ever gotten to read about it in books!
Tip 2: Read Books – These are the absolute best to start with (and keep on the building site):
“Building Green” It is worth the price of the books alone just to ogle all of the gorgeous photos inside!
Tip 3: Practice!
One of the best ways to practice the art of cordwood building is to build a test wall or small project like a chicken coop, playhouse, or storage shed. You might even join someone on their cordwood build if you know someone. But what if you are unable to do this?
Our solution: Build test “columns” that will be used as the butt ends for larger walls.
Our main house walls are 16 inches thick. However, the posts in our house frame are only 6 inches wide, which means we have a 10 inch difference where the cordwood walls meet the posts. Mark mounted posts made of some extra 4×6 lumber we had lying around, and left a 6 inch gap in between the main post and the “fake” 4×6 post.
This created a 6×16 inch column that we then filled with our test cordwood. Below, you see the our actual structural 6×6 post on the left and the fake 4×6 post on the right. Mark is starting the first course of mortar at the bottom.
We then filled with small 6-inch logs up the height of the column, making sure to offset logs as we went. It is important to offset the logs to avoid having straight lines of mortar because straight lines of mortar weaken the structure.
Tip 4: Make it a team effort!
Cordwood building is not a quick process, unlike traditional stud framing. Normally, you’d just slap some 2×6’s together and add insulation and sheathing of some kind, but that’s not the case here. I wish we had an army working on these walls just so it would go faster, but that isn’t always practical.
With at least two people though, there’s always someone to be mixing/pointing mortar or pouring insulation while the other sets logs in the wall or something.