I don't know the first thing about cordwood building but I have been reading the journal of a person who is building a cordwood house. There is a lot of information on this site.
Its called Daycreek.

Here is a link that might be useful: Daycreek

boy-i am so excited that you brought this up.I have a couple of books/video on cordwood.Wanted to build my house that way-still plan to do my addition in cordwood.hubby says i have to convince him so i plan to build my hen house this spring.They show a lot of round building but that would be too funky for hubby.i have to humor him as he will be cutting the wood up.sons-in-laws are carpenters-they just try to humor me hoping the urge will go away.i have to convince them also so they will be nice and roof it for me.

John -
Thanks so much for the link - there are a lot of good articles under "cordicles". Thanks very much!

Zuke - A hen house sounds great! Please let me know how it comes out!

Glad this was brought up also. I am wanting to build a greenhouse. The north, east, and west would be the cord log and the south glass. My mom has some books and I am picking them up next week. If I learn anything I'll let you know. Mom said they also added glass canning jars. Imagine that!

Hengal, did you ever find your info, or build anything from cordwood? We have Richard Flatuea's book. Think his is the best. lilga.

Check countrysidemag.com as they very often have articles from people about building with cordwood and articles on how to...a reaqlly great magazine for people interested in homesteading or just learning good and interesting things.

Hengal, Lovezukes, & Mary1990,
Did you ever build with the cordwood process?
Just found out about this via a magazine article, and want to build a greenhouse using salvaged materials. Have windows, lot of old wood, and wanted input/feedback. Realize this is an old thread, but . . .
Anyone?
Thanks!
rosebush

Quite a lot of years ago, I was hired to help in the construction of the walls of a cordwood house. I seem to remember I was mixing the mortar/chinking "mud" and cutting wood to length with a chainsaw. It was just a job and I didn't know the people who were going to own and live in the house, and never set foot in it in the later stages of construction.

That meant that I did not really learn how adequate and satisfying the house turned out for people living in it. But working on it, and knowing the climate of our area (which is sub-freezing for most of the winter, especially the nights), generated a number of questions for me.

One of the issues, I'd think, would be cold-air infiltration in winter. Wood generally shrinks over time as it dries out more and more over the years. The roundwood sections might check (split along their length), allowing air to move through. Also, the mortar/chinking might imaginably pull away from the surfaces of the roundwood sections not only due to long-term wood shrinkage but also due to a differential expansion and contraction of the two materials (wood and mortar) due to temperature and moisture during the yearly weather cycle.

Remember also that in winter, the outside ends of the wood (in, say, zone 6 or colder) will be exposed to cold air, while the inside ends will be exposed to quite warm air. That in itself is an interesting physical influence to contemplate.

For me, all of the above boils down to the fact that I personally would really want to talk with some people who have lived in and maintained a cordwood house over a period of four or five years or more. Since I'm not one of those people, I'll bring my comments to a close here.

Joel

Thanks for your input! From what I've been reading, it looks like a really good and inexpensive method.

rosebush,

Stressed cordwood is about half the cost in materials as stick frame construction. Infill cordwood is only a third cheaper than stickbuilt.

That of course, does not include finished costs, (windows, doors, wiring, plumbing, flooring, cabinets, counters, bathtubs, etc).

Cordwood is only cheap if you have access to cheap or free timber and labour costs are not high or are free. It takes a lot of mortar and a lot of time to build with cordwood.

Jaybc,
I have access to lots of free timber and can get help from nephews, son-in-law, etc. A small garden shed/greenhouse using salvaged materials seems do-able. I also have heavy barn timbers/beams, old windows and plenty of room to try it.
Thanks!

R value of wood is 1 per inch. 16" wall with mortar couldn't be better than R12. Cordwood has only one thing to recommend it: low cost of materials. All other aspects are a loser.

fruithack,

the R value of wood varies considerably.

"The R-value for wood ranges between 1.41 per inch (2.54 cm) for most softwoods and 0.71 for most hardwoods. Ignoring the benefits of the thermal mass, a 6-inch (15.24 cm) thick log wall would have a clear-wall (a wall without windows or doors) R-value of just over 8.

Compared to a conventional wood stud wall [3 inches (8.89 cm) insulation, sheathing, wallboard, a total of about R-14] the log wall is apparently a far inferior insulation system. Based only on this, log walls do not satisfy most building code energy standards. However, to what extent a log building interacts with its surroundings depends greatly on the climate. Because of the log's heat storage capability, its large mass may cause the walls to behave considerably better in some climates than in others.

Logs act like "thermal batteries" and can, under the right circumstances, store heat during the day and gradually release it at night. This generally increases the apparent R-value of a log by 0.1 per inch of thickness in mild, sunny climates that have a substantial temperature swing from day to night. Such climates generally exist in the Earth's temperate zones between the 15th and 40th parallels."

A 16 inch wall of cordwood, made of Lodgepole pine will have a calculated overall R value in excess of R 22.52.

The standard for R value on Lodgepole pine however has been historically measured across grain where the greatest energy loss occures. In cordwood construction the R value needs to be measured across endgrain.

Recently, with the popularity of cordwood construction, recognised non-partisan councils have started taking in situ endgrain measurements with surprising results.

The BC Resources council found an R value of between R34 and R39 on their 16 inch Lodgepole pine wall samples.

The BC Ministry of Forestry found an R value of between R35 and R42 on their 16 inch Lodgepole pine wall samples.

R values are of course a simplistic measurement of insulative value, there is radiant heat loss to be considered, thermal sink functions and many others as well.

The BC Energy Council has found that a properly built cordwood home with 16 inch softwood walls is on average, 48% more efficient than 2 x 6 stud walls with R22 and a vapour barrier, when the measurement used is simply the amount of energy required to keep the home at 18c for one month in temperatures below -15c.

YMMV.

Considering wood to be effective thermal mass? Thermal mass uninsulated from exterior? R value differences of .1 per inch? Traditional log construction as a basis of comparison for energy efficiency? Couldn't find anything with quick searches of BC etc. Canadians do take their energy efficiency seriously.

fruithack,

wood is not solid, it is composed of millions of hollow capsule shaped cells (like a gram type bacteria or a Tylenol Cold and Flu capsule) with an outer wall of cellulose. Heat loss is along the perimiter of the cells, ( the cellulose structure) and the rate of heatloss is affected by the temperature of the air in the hollow center of the cell.

Contrary to popular opinion, Wood cells are not like bundles of drinking straws with open ends.

These cells are aligned vertically to create grain and as a result, traditional measurements of heat loss are taken across the grain, where the cells are thinnest, in both hardwoods and softwoods, rather than along the grain, where the cells are longest.

In one test on 4 x 4 Lodgepole pine samples, the R value across the grain was R 5.49 in one direction, (as aligned to the growing tree, this would be measuring from the heartwood to the sap wood), in the other direction was R 5.67, (as aligned to the growing tree, this would be measuring across the heartwood and sap wood), and when measured along the grain, (as aligned to the growing tree, this would be measuring up the tree), was R 6.24.

These are significant differences in R value.

R Value is also a very simplistic measurement of heat loss, that does not accomodate for radiant heat loss, or thermal mass.

Radiant heat loss can be extremely important because it actually has more impact on how humans "feel" hot or cold than room temperature.

Thermal mass as well is very important. In a simplistic explanation, thermal mass is how adobe homes, stone and brick cottages remain habitable with out wall insulation. Stone, mud and brick all take large amounts of energy to warm the surface and some of the thickness, but once warmed to a certain point, release that heat energy faster to the surrounding air, than they migrate that heat through the thickness of the walls.

So, in a stone cottage in Scotland, once the interior is heated, heat from the heat source and released from the walls radiates inside the home while the out side of the wall remains below freezing. In an adobe house in Arizona, the sun heats the outer wall, but the mass releases the heat to the outside air, and the interior of the home remains cool.

Some studies have shown that you are better off adding another half inch layer of drywall, ( almost doubling most homes thermal mass), than adding insulation to the exterior of a 2 x 4 insulated stick frame home.

R values are convenient, easy to measure and simple to calculate. Radiant heat values and thermal mass are much more complex.

The only "true" measure of a homes efficiency is to heat it to a comfort level, hold it at that comfort level, ( or cycle it through the daytime comfort level and night time comfort level) while measuring the amount of energy used. Even this can get quite complex, as there is a requirement for fresh air exchange inside the house, passive solar heating, etc that all affect the final result.

Like strawbale homes, adobe homes, and earth sheltered homes, cordwood homes have advantages that suit certain places, certain people and certain times. They can be as, if not more energy efficient than even SIP Panel homes and as long lasting as stone or brick.

Around here, we have witnessed an "explosion" of non-traditional housing, almost all of it is ownerbuilt. The economy is not that great and has not been for close to 50 years, so traditional housing here has been mobile homes, modulars and stickbuilt. About an eighth of the housing is stick built 2" x 4" additions on 80 to 100 year old log homes.

There are two major "cheap" sources of timber here. The first is beetle killed Ponderosa Pines, which have caused the explosion of new log homes and log additions, ( 12" to 24" thick walls). The second is beetle killed Lodgepole pines and spruce, which has caused the growth of cordwood homes, (16" to 24" wall thickness constructed of 6" to 12" diameter chords).

The other major growth is strawbale, as we are a agricultural hay and pastureland region and straw is cheap.

With money being tight, energy being expensive, many farmers are embracing alternative building techniques last used 100 years ago up here. Some results are very efficient, some, not so much.

Your Mileage May Vary.

I do not have first hand experience with cordwood, but everything I hear scares me a way from using this method to build a residence. I do think it is a spectacular method to build barns, storage buildings, and other miscelaneous outbuildings. There are many green building methods, and the best should be chosen for specific location and available building materials. Several Green Building Methods are detailed here.

Good luck

jaybc, your description of thermal mass is in defiance of the laws of thermodynamics.

Thermal mass doesn't mean there's a greater release of heat to the hot side. That's flat impossible and is a gross misunderstanding of what thermal mass means. If you could get anything to release more heat to a hot side that a cold one, you could make a perpetual motion machine. Seriously.

Thermal mass is excellent ONLY in areas in which there is a large temperature swing between day and night with a happy medium in between and/or where there is a great deal of solar radiation even in winter (though with cold air temps) during the day despite cold nights. Translation: high-altitude southern deserts are the ideal place for high thermal mass. What happens is that the wall serves like a battery during the day, absorbing heat--from whatever side of the wall it's available from. Then, at night, it releases the heat--actually, it will release MORE of the stored heat to the colder outside than the warmer inside! But that's okay as long as you got enough heat from the outside in the first place.

When you don't have a climate in which the wall is charging from the outside during the day in winter--that is, when there isn't sufficient energy from temp/radiation combo'd such that it is greater than the total energy contacting the wall from inside the house--then what you get is a virual hose sucking energy from inside the house and dumping it outside, 24/7.

Take away: Designing thermal mass in an exterior wall is a very bad idea in most climates.

The best solution for most climates is to have thermal mass interior to the house. This would be an internal, thick, high-mass wall that gets the light from a bank of south-facing windows. If you're really smart, you'd integrate it with your masonry heater. And you'd find an appropriate material to build it out of, too--there are a LOT better choices than wood. (Specific heat, etc.)

I'm planning a cordwood structure of my own in North ID and have helped out / participated in building cordwood infill a number of times. My obervations?..

Thinner walls (8" or narrower) are more exacting to build - you have to pay attention to warp as you stack, and the mortar / infill beads are too narrow for easy work ... But you do make efficient use of the wood youve cut! I like working with thicker walls: 12-16" thick or more.

Pay attention to mortar plasticity... Too dry and your batch won't be workable for long and will be crumbly when it comes to pointing (finish work)... Too wet and it'll be slumpy and get cracks as it dries. Mortar that packs like a snowball is just about perfect.

Pay attention to fit of the pieces you stack... Keep a variety of sizes on hand as you work so that you can fit stuff where it works and keeps the mortar joint an even width... All same size wood can be trouble,