There was a bit of a buzz in the green building world this week around the announcement of a new development of straw bale houses. It’s the first time that straw bale houses have been built for the open market. All previous examples have been self-build eco-home projects, and it’s great to see the technique take a step towards wider adoption.
As any sustainable architecture geek can tell you, straw makes a great building material:
- It’s a great insulator, meaning straw bale houses need very little heating and can even be built to passivhaus standard. That’s efficiency savings year on year, lower bills and lower emissions.
- It’s entirely renewable and readily available.
- Straw is a waste product, so using it in building creates value from the waste stream.
- It can be sourced locally, reducing transport emissions.
- The two above factors make it very cheap.
- Since the straw doesn’t rot down, it locks away the CO2 that the plant accumulated while it was growing, making straw bale building a carbon neutral or even carbon positive building technique.
- At the end of its lifetime, the straw is entirely biodegradeable, unlike the mixed building waste usually left after demolition.
The current development is in Bristol, and consists of seven new homes in a block. To match the other houses on the street, and as a condition of planning permission, they will be clad in brick. Inside, they’ll be made from pre-fabricated wood and straw panels made by a company called Modcell.
Modcell have laid the groundwork in straw becoming a mainstream building material. They’ve been experimenting and testing it for a decade, subjecting their panels to hurricane force winds or simulated floods and seeing how they stand up. They also built the demonstration Balehaus at Bath University, allowing them to test efficiency performance with a real building. Studying a building over time has allowed them to secure the highest standards of safety and performance. Without certification, it couldn’t be used for a commercial build – nobody would insure it, or give you a mortgage on it.
There are hundreds of straw bale houses around Britain, and other buildings too – a business park in Bradford, and several schools. Houses built for sale on the open market are a positive step towards more mainstream use.