Using compacted soil as a building material is as old as the hills. Many examples are found around the world. A rammed earth house, however, is nothing like a mud hut and need not be primitive. It’s a lost art well-suited to sustainable home construction today. When using the proper types of sand, clay, and other excavated materials, these structures can stand for thousands of years. They built the Great Wall of China from rammed earth some 8,000 years ago.
Like cob and adobe, you use locally sourced materials to make a rammed earth house, but the first two incorporate fiber into the mud. Rammed earth construction isn’t done with mud or fiber, but uses almost dry soil and rock sediment blends packed into forms to the consistency of concrete. And while it is similar to concrete on completion, it’s far more environmentally friendly. It’s also a lot more colorful and attractive. The range of color can blend in with any site’s natural terrain, or be altered with natural earth pigments like the home at the top of this page with its plum-colored walls.
With thick walls of natural insulating materials, rammed earth buildings are cooler in summer and warmer in winter. In extreme climates, incorporating straw into the earth walls achieves greater temperature modulation, allowing for using far less energy to maintain a comfortable indoor environment – no matter what the weather is doing outdoors. And don’t get the mistaken idea that earthen walls are only suitable for a dry climate. When done right, not only does it regulate humidity, but is extremely moisture resistant.
Also known as ‘pisé de terre’, this age-old building technique is making a comeback due to the great potential it offers modern structures. Not only are they energy-efficient, you could never burn one of these houses to the ground. Rammed earth homes are also maintenance free, pest proof, sound proof, and organic! They contain no synthetic materials – at least not unless you choose to use something not made from natural materials. However, in an earthquake zone, you would want the added strength of special engineering in your walls, which does incorporate non-organic materials. And if you want a passive home, this is far easier to accomplish with rammed earth construction than traditional wood or brick building materials.
So, how do you get such a house? There are builders who specialize in rammed earth construction in both the US and Canada, Mexico, the UK, Europe, China and other parts of the globe. You could also build it yourself. Currently, one couple in New Zealand is working on building their own passive rammed earth home and will learn the art hands-on this summer from SIREwall in Canada. You’ll find rammed earth construction courses available from others too in North America, the UK, and beyond.
Another plus to these super sustainable homes is that you can build them in any style from sleek and modern to traditional or rustic. Want a curved wall? No problem! It’s much easier to do with rammed earth than other materials. Prefer a brick look? Rammed earth works beautifully for making bricks too.
- USDA Farmer’s Bulletin (1926)
- Architecture Now
- Green Home Building
- Earth Architecture