Rammed earth is perhaps one of the greenest building materials. It doesn't get more local, has terrific thermal mass and many earth buildings have lasted centuries. Avantika Chilkoti has written Mud World, a terrific overview of it in the Financial Times. There's a Paywall around the FT as thick as the walls they describe, and you might have to register to read it.
The article covers the work of Martin Rauch, who notes that interest in once-common earth building is rebounding:
“With industrialisation and the railway, it became easier to transport energy and building materials, so it wasn’t necessary to build with earth any more,” says Martin Rauch, a ceramic artist turned architect championing the use of earth for sustainable construction. It became a poor man’s material and the image is hard to shake. But in the past 15 years, rammed earth has returned to the limelight as human and environmental health have become key concerns.
(See Rauch's house in TreeHugger here)
Anna Heringer, architect of the wonderful prize-winning Handmade School, describes how there is a social justice aspect to it as well.
We often think of sustainability in terms of high-tech solutions and it isn’t possible for everyone in the world to have high-tech solutions. That’s exclusive, which isn’t sustainable. Building with earth, you can have a lot of people involved – it’s about communities too.
Those lines in the wall of Martin Rauch's house in the photo above? they are layers of stone installed to protect the wall from rain, the dissolver of rammed earth walls. But as the author notes, give a building "a good hat and shoes", and it can last a long time, no matter what it is made of.
Good reading in the Financial Times