The foolish man built his house upon the sand, goes Jesus’ parable. But if he’d built it out of sand, that would have been a different story altogether. Assuming he was using Mike Tremeer’s sandbag building techniques, that is.
Developed in South Africa, sandbag buildings are an affordable do-it-yourself approach to sustainable housing. The House of Sand company can send you a kit comprised of specially designed beams, lots of empty sandbags and a couple of truckloads of sand. Once the frame is up, you can call in the neighbours to help you fill the sandbags and stack them up. The building can then be finished and plastered as usual on the inside and outside.
There are lots of advantages to building with sand in this way:
- Sand is cheap. Depending on where you’re building, you may even be able to gather it on site. That keeps costs down and reduces emissions from transport.
- Anyone can stack bags. It’s unskilled and saves money on bricklayers, and no specialist machinery or equipment is required.
- It’s very fast, and you can erect the basic structure in a couple of days.
- Sand is a natural material, with much lower embodied emissions than bricks and concrete.
- Walls made from sand have a high thermal mass, keeping the building cool in summer and warm in winter.
- They are also wind and waterproof, fire resistant, and soundproof.
The sandbag housing concept is perfect for social housing, making it a green building technique that benefits the poorest. It is empowering as well as environmentally sound. The Freedom Park development below was built for former slum residents, and families moved out of tin shacks into these colorful new homes. The sand was gathered from nearby dunes by local people, who then filled the bags and built their own houses under the supervision of a Cape Town architect. The cost? Less than £4,500 each.