Cordwood Construction Jack Henstridge and the Cordwood Movement

Thoughts from Jack Henstridge The Godfather of the Cordwood Movement

Compiled by Richard & Becky Flatau. Edited by Jack Henstridge for the Cordwood Conference Papers 2005.

Two wonderful pictures of Stackwood Jack Henstridge!

Just as James Brown is the Godfather of Soul Music, Jack Henstridge is certainly the soul of the cordwood movement. When we built our cordwood home in 1979 Jack was there with encouragement before we started, consolation when we learned the true meaning of “sweat equity,” praise when we proudly completed our task and uncompromising friendship ever since. These next paragraphs come from Jack’s phone calls and letters.

Jack wrote the book Building the Cordwood Home in 1977. He has taught cordwood courses at universities and other institutions throughout North America. He founded the Indigenous Materials Housing Institute in 1980 to conduct research on “do it yourself house construction”. He has published articles in numerous magazines and newspapers. His latest book is entitled About Building Cordwood.

What is the main reason for building with cordwood?

Cordwood Construction is a simple, easy way to build yourself a comfortable structure, without spending an arm and a leg. It is a very simple and easy process. If you can pile wood, you can build cordwood. Compared to other methods of “sweat equity housing” Cordwood Construction gives you the “best bang for the buck.”

How did cordwood get re-started?

The first question to ask is “Why did it stop?” The mortar that was originally used was a mixture of lime and sand. This was much better than the clay and straw that was originally used as “chinking”, but there were still a couple of problems with it—first you had to find a source of lime and if you had no access to natural lime “i.e. gypsum deposits” you made your own by burning oyster shells, clamshells, limestone or whatever did the trick. The second problem was that it didn’t “weather” very well. It took a long time for the lime to calcify in the mixture and it would “weather out.” The early cordwood houses (circa 1800s) have either been sided over or the mortar has eroded. The main reason that cordwood fell out of favour was the invention of the circular saw. There was a time when everyone built their own home, primarily log cabins. Cordwood, stackwall or whatever the locals called it was just another option. The circular saw made it much faster to produce accurately sawn lumber and “the building boom” got underway. Cordwood started as low-cost housing. Some structures that were built over 100 years ago in North America are still standing and in use. In the 60’s & 70’s people were again looking at a “back to the land,” sustainable lifestyle. Cordwood enjoyed resurgence because we now had portland or hydraulic cement that would harden even underwater. Cordwood had always been low-cost, do-it-yourself housing. Recently it has begun to appeal more to mainstream society interested in building beautiful, unique log homes while incorporating the latest technologies. Some of the newer cordwood homes, like their predecessors, are works of art.

Tell us about your latest innovation “cordwood for tornado alley.”

One of the problems in housing today is that very few people consider the aerodynamics of the house. You want to have a house that the air flows around and not one that it “butts up against.” There are no square tree trunks in nature. This is why I am an advocate of curvilinear structures.

A woman in Kansas, right in the Tornado belt of the lower Midwest, asked me to design a cordwood home that would be able to withstand a tornado and still be functional and attractive. The model in the photo gives a “bird’s eye” view of the concept. It is a circle within a circle, low to the ground and strong. The inner circle is an atrium. It is meant to sit on a hill and be bermed on all sides.

First of all, let’s get one thing clear- anything “proof” is just a figure of speech. A much better word is “resistant.” We really don’t know how hard the wind can blow, the earth shake, the rain fall or the water rise. All you can do is try your best to “cover all the bases” and be ready to roll with the punches.

In almost all of your designs, you seem to prefer arched openings rather than rectangular. Is this just for aesthetics or is there another reason?

Very definitely another reason: The ancient Romans discovered the principal of the arch and a great many of their structures are still standing after thousands of years.

If you are going to have an opening in the wall why not make it an arched opening? Not only is it stronger than a rectangular opening, but it’s also real funky.

Some people feel that it looks “too churchy.”

Well, not exactly, those early Romans with their gladiator games, barbaric treatment of prisoners – and let’s not forget orgies and other such sports—were far from being “Churchy People.” However, they were fantastic architects, engineers and builders. The early churches, cathedrals and castles used the arch technique because it was the best way to go. I feel the same way about incorporating them in your cordwood walls. It’s a matter of preference.

Back to the model- What size does it represent?

It’s built one-quarter inch to one foot, which gives it a forty-five-foot diameter. I wouldn’t go any smaller than that for this house. This house is designed to shelter two children and two adults plus enough room for a couple of overnight guests

What about storage space?

One of Murphy’s Laws states “junk expands to fill the space allotted “. Believe me; I know this to be true! With cordwood, you can always build an adjacent workshop, garage or whatnot.

What advice would you give to people building with cordwood?

Build with adequate roof overhang. “Splashback” is not really a good thing. You don’t want water running down your walls.
Use good quality wood that is barked, rot-free and well dried. Splitting helps to speed up the drying, stress-relieve the block and thus eliminates “checking.”
My favourite mortar mix is (for a load-bearing wall): one portland, two soaked sawdust, three aggregate. For non-load bearing walls, simply double the amount of sawdust. The sawdust holds moisture within the mix, allows the mortar to cure rather than to dry out. If it cures, you have a strong wall, if it dries out, the mortar crumbles. It should take about a month to cure properly.
I prefer coarse sand and pea-sized gravel and even larger for the aggregate. This works very well because the cement, which is an adhesive, has better surfaces to grab onto. It’s not like laying up bricks or stonework where you have a relatively thin bead of mortar. Personally, I don’t like to see any mortar joint less than one or two inches wide. You must realize that what you are actually building is a mortar wall. The blocks of wood are a sort of form that controls the width and direction of your wall and fills the spaces in between the mortar web. This is the reason that I came up with “The Mortar Stuffer’s Certificate” because that’s what you do to make your wall strong. That’s what holds it all together.
To find out if the cordwood method is for you, build a small structure, a shed, a doghouse or even a small wall. Then you will know.

What was the inspiration for your wonderful Master Mortar Stuffer Certificate and what do all the drawings mean?

When I came up with the idea it was sort of “tongue in cheek.” It wasn’t meant to be serious. People seemed to like the idea so I started mailing out the certificates to people who had completed their own structures all over North America. Personally I think it is time for something new, so I’ve come up with something to fill the bill—and you’ll have to agree—totally original. I haven’t come up with the artwork yet. I think we should call it the “Cordwood Constructors Commendation” We could call it the CoCoCo Award.

The gloves and trowels are self-explanatory, especially after you’ve mortared up a few walls. The Viking ship represents the introduction of cordwood to North America. There is lots of evidence being uncovered that it was quite common in Scandinavia. The first cordwood in North America was in L’Anse-aux-Meadows (Lansing Meadows), Newfoundland at one of the earliest Viking settlements. The flight of the saucers from left to right is there just in case someone brought the idea here from somewhere else. The Wood Nymph signifies the experience that lots of people have when they are building. The wood will talk to you and tell you where it wants to go in the wall. The Indigenous Materials Housing Institute symbol is in the lower right-hand corner. It represents environmental coexistence. The diamond on the gloves in the upper right-hand corner is what they are worth to protect your hands. This is self-evident if you have ever had a cement burn.

How has your house held up over the last 30 years?

Jack’s Ship with Wings cordwood home.

No problems whatsoever. Our walls are only 9” thick. We still have some air infiltration and this is just because I haven’t gotten around to chinking it yet, but it isn’t that big a problem. In fact, I think it’s a plus. I can count on one hand the number of times anyone here has had a cold or a stuffy nose. We don’t need an air exchanger. An airtight house isn’t necessarily a good thing. You want your house to be able to breathe.

Any nitpicker can find lots of small mistakes in a cordwood home. Most of the people who build them are amateurs. The feelings of achievement and savings far outweigh the tiny oversights. Look at the big picture and see the accomplishment.

What would you recommend?

I would recommend walls at least 12” thick and no thicker than 16”. These sizes stack very well vertically and give you plenty of thermal resistance. It’s easy to mortar both sides of a 16” wall without having to move to the other side except for final pointing. Anything thicker than this is entirely up to the builder. It depends on wood supply, personal preference and dollars available.

At the present time, I am trying to develop a mixture that won’t crack or at least keep cracks to a minimum. I have tried a mixture with an additive called “Fortafibre” that looks quite promising. But I think the answer may be a trick used in Asian countries, Bamboo Fibre. While it isn’t too strong in compression or sideloads, it is fantastically strong in tension and that’s where you want it in the mix. Bamboo isn’t all that hard to come by and I am almost convinced that it has great potential as a mortar reinforcement.

Would you care to share a story or an anecdote that you find especially appealing?

We were building a demonstration cordwood building for the MOFGA (Maine Organic Farmers & Gardeners Association) Fair at Litchfield, Maine. We erected the building in three days. We had two cement mixers going, lots of rubber gloves and everybody pitched in to try the technique, including the Governor of Maine. Every day there was a man who stood on the sidelines and watched what was going on. By the third day, I walked over and asked him what he thought of the building. With his typical Maine drawl he said, “What’s the matter, you think someone is gonna steal your woodpile.”

Another one that I remember was at the first “Mother Earth News Seminar.” I was talking about the problems that most people create when they are contemplating a house design. Their primary concern is “What’s it going to look like on the outside?” And the last thing they consider is “How are you going to ‘live’ on the inside? “

One man held up his hand and asked me to repeat what I had just said. I asked him if I wasn’t speaking loud enough and he said “Oh no, I just wanted to make sure that my wife heard it.” That broke everyone up.

Jack leading the 227 attendees at the Cordwood Conference 2005 in Merrill, Wisconsin.

“In these days when so much of a building seems to be pasteurized and when the architecture of the world appears to be approaching the state of universal homogenization, it is rewarding to discover and use an indigenous “building system” that is so naïve and yet paradoxically, so truly sophisticated.”

William G. Grierson, Architect and designer of the Ferguson “Cordwood Retreat”

Jack passed from this like in October of 2006. He is fondly remembered and sorely missed. Rest in peace dear friend…