Geopolymer Stones & Earthbags
Voting is heating up at The $300 House Open Design Challenge. This design challenge started out as an idea described by Vijay Govindarajan and Christian Sarkar in a blog post at the Harvard Business Review. They proposed that it might be possible for a simple home to be built for less than $300.
After looking through all the designs I can’t imagine any of them costing less than $300, except for some of the earthen homes.
Vote for Owen!
Earthbag design-build expert Owen Geiger has two three designs entered in the competition and they are doing well, but every vote gets him closer to winning. Can you spare a vote?
- $300 Earthbag House — What the World Needs Now – An expandable design easily built by novice owner-builders.
- Stone Dome — $300 Geopolymer Earthbag Dome – My personal favorite, a synthetic-stone earthbag dome (pictured here).
- Update: $300 Geopolymer CEB House – Just hours after posting this article Owen let me know of a third entry. CEBs are compressed earth blocks.
Geopolymer Stones & Earthbags
While I’m a big fan of domes, what caught my eye was the building material - a geopolymer earthbag.
The Geopolymer Institute has been trying to recreate a building method they suggest was used to build the pyramids of Egypt. What they (re)developed (depending on your point of view) was a way to build artificial limestone stones from a mixture of limestone, kaolin clay, sodium carbonate, lime and water.
You basically mix the stuff up, let much of the water evaporate, then tamp the semi-moist mixture into a form – or earthbag! After the stuff cures you’d have something as strong as stone – without the need to quarry and sculpt blocks. You could also think of geopolymer as a cement, but without the large amount of energy input required to make modern cement.
While the whole Egyptian pyramid piece would be an incredibly important historical puzzel to solve, I really think the value of (re)discovering this low-cost & low-tech building method could far outreach solving the mystery of the Great Pyramids.
Owen Geiger’s adaptation, packing earthbags with a geopolymer material, could make this building method even more accessible. Earthbags also provide more flexibility than wooden forms because all sorts of shapes and structures can be built by stacking up earthbags.
Below is a video from the Geopolymer Institute that shows how a giant synthetic limestone block is made. The jury in my head is still out on the whole pyramid debate – so while this building method seems so much more plausible,I’m not going to let it distract me from the material itself.
Similar Posts:
- Geopolymer Stones & Earthbags
- $300 Earthbag House
- $300 Earthbag House
- $300 Compressed Earth Block Hybrid House
- Vote Now for Shed of the Year 2011
