Wattle and Daub

Humans have built with earth for more than 10,000 years, and earth buildings are found on every continent except Antarctica. Here in Britain, earth building usually takes the form of wattle and daub, clay lump or cob. All of these techniques rely on clay to bind together different subsoils such as sand and gravel. In cob, the subsoil is sculpted directly into walls; clay lump is a a method of making subsoil into unfired bricks, and wattle and daub uses small timbers (wattles) to support the subsoil mix, known as daub.


There was plenty of ash coppice available on site, so we used this to make the wattles. We sprung ash uprights into pockets cut into the oak frame, and then wove smaller ash poles between the uprights. Hazel is the more traditional material for wattling, but ash works fine too.


The mix for cob, clay lump and daub is basically the same: clay, aggregates such as sand and gravel, and straw. The proportions can be varied according to the subsoil available. The soil beneath our foundations was almost pure clay, so we had put this aside while digging the foundations to use for daub. We mixed clay and sand 50:50, and added about one bale of wheat straw per tonne. This gave us a mix which clung to the wattles, didn't shrink or crack too much while drying, and set very hard.

We trod the mix underfoot, turning it on a tarp. Our building needed a relatively small amount of earth, since the walls are only about 6" thick. For buildings which need more earth, such as cob buildings whose walls can be up to 2' thick, it would be more practical to use a minidigger to mix the subsoil.


Applying daub to wattle is easy and fun, especially when lots of people get involved.


Earth building lends itself to sculptural creativity. Here, a niche has been built directly into the wall.


We chose an earth walled building for several reasons. Firstly, we wanted to use as many materials from the site as possible - the subsoil came from under the foundations and the straw from a couple of fields away. Secondly, we wanted to involve volunteers in the construction, and daubing is something that anyone can join in with; it's arduous but fun, and many hands make light work. Third, we wanted to minimize the environmental impact of the building. Although earth is not a great insulator, this is a building that will be used in the summer and doesn't need to retain lots of heat. Using earth means that the building has a very low embodied energy - little energy is expended in the extraction, processing and application of the materials. We just dug up the earth and mixed and applied it by hand. Bricks, on the other hand, are mined, fired and transported large distances, all of which is very energy intensive.
An earth wall also has the advantage of being breathable; it can absorb and release humidity to create a stable environment which doesn't suffer from dampness - this is useful in a shower block.