Variations of Clay, Sand and Straw
I’ve been enjoying the latest newsletter articles by Coenraad Rogmans over at House Alive!. In the article, Building with Sand, Straw and Clay, Coenraad talks about the many variations of the magical mixture of these ingredients. There is a spectrum of ratios that create different variations of these base materials. Including cob, light clay, wattle and daub, bale walls, bale cob, earthen floors, plasters, renders, and paints . Within each application one would use a different ratio for a particular result. Say for instance you are working on a cob wall with built in niches. Ianto Evans teaches about corbel cobs. Cob with long stocks of straw for added tensile strength. Another is light clay, a mixture of straw tossed like a salad with the dressing being clay slip, or watered down clay. Or for an earthen oven a sand clay mixture. You can see how versatile it can be!
Depending on the ratio one can create a suitable building material for a specific purpose. Light clay is not load bearing, so you would need to use post and beam to bear the weight of the roof. Cob can bear weight with no need for other load bearing structure, though it can also be infill. Bales can be both load bearing and infill and offer a massively thick wall without the on site creation of the wall volume and can be plastered with earth. There are as many incarnations of these variations as there are building sites and builders.
Many people are using these techniques to create hybrid natural buildings. Where one uses the particular variation for it’s best use. Strawbale walls for increased insulation in cold climates; thick cob wall for solar heat absorption and sculpting; 2 x 4 wood and pallets for a wattle and daub interior wall. For the finish, all can be covered in a earthen plaster and alis or clay paint.
I am surprised and delighted with the results of this triad of natural materials. While digging from the earth it often occurs to me… I am making shelter with the Earth. Hello pile of earth, you will make a beautiful wall. Direct, simple and wonderful.
“Earth turns to gold in the hands of the wise.” — Rumi