Frequently Asked Questions About Cordwood Masonry (a.k.a Stackwall)
What is cordwood masonry?
A. Cordwood masonry is a wall building technique commonly used to build homes, barns, saunas -- just about any structure that uses walls above grade. The walls are comprised of debarked cordwood and some form of a mortar. The widths of the walls are equal to the length of the cordwood. Typical wall widths vary from 8" to 24". Various species of cordwood can be used and typically builders use species that are commonly found in their area.
What is the difference between cordwood masonry and stackwall?
A. Cordwood masonry, cordwood construction, stackwall, log-end and stove wood all describe the same type of housebuilding method. Canadians tend to favor the word stackwall while us Yanks tend to use cordwood masonry. Other names for cordwood masonry are: stovewood, stackwood, log-end and cordwood construction.
Where did cordwood masonry originate and how long has it been in use?
A. Cordwood masonry's origins are unknown. There are some homes in Canada that are between 100 and 200 years old. In the United States, there's a house at the Old World Wisconsin Museum that was built in the 1884, complete with a cordwood chicken coop. There are also known examples over 100 years old in Sweden.
How much does it cost to build a cordwood home?
A. This varies based on how much of the labor is done by the builder and by the materials used. If you have your own supply of wood, the only cost to building a cordwood wall is the mortar and sand. The foundation, roof, floors, plumbing, electrical and fixtures are all up to the home builders discretion and therefore can vary the cost greatly. If one fells their own trees and barters construction materials, a house can be built for around $10 per square foot. (Cost of well, septic and electric not included.)
Are there any species of cordwood that are not recommended for building cordwood
A. It is best to use softwoods but if in your area hardwoods abound, it is still possible to use them in certain circumstances.
Different species of hardwoods can have quite different expansion capabilities. It is highly advisable to build a test wall first to see how they expand after being mortared into the wall. IF the hardwood is extremely dry, there's a chance that the wood will significantly expand causing structural damage to the wall. (There is a known instance in which oak cordwood expanded to the point that it lifted a post and beam frame off of a bolted foundation plate. ) Test first!
How do you know when the wood is dry enough to build a cordwood wall?
A. The debarked wood is dried just like any other piece of firewood. Under protective cover, wood is typically dry in 6 to 12 months depending upon the species and weather conditions. If you take two pieces of wood and hit them against each other they should make a "clinking" sound. If they make a "thud", there probably still too green.
Do the logs shrink after a while?
A. Yes, this is true. Especially after the walls are dried out by internally heating the house. There's a good chance that you may need to caulk around the logs after a couple of heating seasons, but you should only need to do it once. Silicon caulk or Permachink are commonly used due to their elasticity. The key is to let the wood dry out first before applying the caulk.
A. Not much other than the initial caulking. The walls will probably outlast you as long as there is an adequate overhang on the house to keep the walls dry the majority of the time. Other maintenance such as the roof and internal wear of the house is pretty much standard maintenance just like a conventional home.
A. No, just time consuming. There's a lot of manual labor involved in building a cordwood house. Building the walls can be done by just about anyone, but it is labor intensive.
Do you need to point the mortar?
A. Pointing is the process of smoothing out the mortar around the logs and giving some "relief" between the mortar and the wood. Some people prefer the flush wall look and others like the logs to extend outwards slightly from the mortar. Pointing tends to give the wall a more finished look, but does extend the amount of time that it takes to put up a wall. It's a personal preference.
What's the deal with the bottles?
A. Some builders like the look of adding colorful bottles to the wall. Bottle-ends as they are called is nothing more than two bottles (necks inwards) wrapped in tubing, mortared into the wall. If you want to use colored bottles, make sure that one end is clear otherwise they will be too dark. It's not a necessity, but quite a few builders use them. It also helps bring in outside light to a dark room such as a closet.