I would like to conclude my slide show of pictures from the cob house project of a few years back. I guess the word ‘house’ might be stretching it, perhaps ‘hut’ is more appropriate as the square footage was only around 250.
The work took until late October of that year, and we moved in right after the roof was on. At that point, all the cob was still relatively damp and that first winter was not exactly the coziest. Here’s a picture from the inside soon after we occupied:
We also put a cob floor into the place; this is similar to the wall material except that the clay content is a bit higher, and the straw was chopped very finely:
The cob floor experiment did not go so well however, as it never quite dried properly, was too soft to walk on, and added a lot of extra moisture to the inside of a rather humid space. So, after a month or two, I laid down a moisture barrier, a 2×4 floor and sheeted it in plywood. I’m sure the cob floor, which is still intact under the ply, would have been fine in the long run, however we had to deal with the problem on the spot, so it was a bit of a shame that the experiment didn’t work out as intended.
After a winter and a spring, the summer finally brought the warmth and dryness that allowed the building to cure properly:
The walls dried out after that summer and we never really took them any further. The normal practice might be a final plaster coat or two, then possibly whitewashing with a lime-based plaster (there are numerous possibilities and plaster recipes), but we just left it pretty much as we had completed it. In this next picture, you can see that one wall still has bits of straw sticking out – this was eventually given a rough plaster coat. The project had been an exhausting one, and my partner of the time, though she had worked really hard through the course of the project, once over, she had lost all interest in doing any more, and I felt the same, wanting to put my energies into other areas:
In a large measure, I was hesitant to show pictures of this project on a public forum like this – – in fact, I long felt somewhat embarrassed about the building, since it is so much cruder than the work I like to do and am capable of executing. I’ve managed to overcome my embarrassment however.
I ended up living in that building for a couple more years, with electricity and phone service but no running water. Although the architecture of this little hut is quite primitive, in a similar manner to the observation from temple carpenter Nishioka that I mentioned in the previous post, I found the experience of being in the space altogether pleasing. To lay down in bed and gaze up at the slender bowed logs, wire tires, and rough planking was very satisfying, a diverse and absorbing view. What you saw was what you got, and it was no mystery how the roof was supported- you could see the structure from within. It was a cute little place, and part of its charm came from the crudity.
I found that the cob walls, despite their lack of refinement in surface finish and unsophisticated profile, really gave me some new building insights I hadn’t considered before. You see, clay is a wonderful material to have in a wall. In the summer, the inside of the space was pleasantly cooler than the outside, and in the winter, once the interior fireplace had been on a while, the ‘flywheel effect’ allowed the cob to retain heat and keep the inside constantly warmer and dryer than outside. It was inexpensive to heat. I have huge respect for clay as a material as a result of that living experience. It is exceptional as a controller of moisture in a space, and ‘breathes in a way, gradually taking on moisture and gradually losing it, in response to the climate. It’s non-toxic and low tech, and has low-embedded energy, unlike the conventional building materials we use. Cob works in a diverse range of climates as well. And as for durability, there are 500 year-old cob buildings in Ireland – in fact in wattle and daubed half-timbered English buildings it is the timbers that fail before the earthen wall materials in most cases. So, cob and light clay building techniques associate strongly to the long-view building strategy.
And anyone can do it – make cob – if of good physical health, thus the opportunity for client participation – owner-builder participation – in the building process is there.
I sold that property and moved to Massachusetts. The new owner was a woman who had spent time in Japan and had a strong interest in pottery – in fact the cob hut is now her pottery studio. Though I first built the house with no building permit, it has since received an engineer’s approval and is fully legal. In fact, there have been a number of earthen walled structures erected in various parts of B.C. and the building code is beginning to become a bit more open to natural building, which is a very positive development in my opinion.
I’m not sure I would build in cob again, given the slow-moving and laborious nature of the process, however clay is most definitely going to be a part of the next house I build, and I have given a lot of thought in the meantime to a system of building which integrates the timber frame with the light clay wall, and think I have come to some innovative, low-tech ideas in terms of how to accomplish that, and with a high level of refinement. Maybe one day I’ll get a chance to build something like that.