“In addition to the Durisol stem wall foundation, our project for the teachers’ union office includes two long sections of earthbag foundation to support the floor joist spans inside the building. The inherent insulation value of the Durisol blocks made them our first choice for the exterior of the building, but the extremely low environmental impact of earthbag foundations made them an easy choice for the interior.
Using continuous rolls of polypropylene bag material (this material would be cut and sewn to make rice, grain and feed bags) as a form for a variation of a rammed earth mix, earthbag is simple, durable and low cost.
Between each course of earthbag, a run of barbed wire is used to prevent the bags from sliding against one another. In the case of this building, we required three courses of earthbag. This was topped with a 2×8 sill plate on which the floor joists will be fastened. The sill plate is attached to the bags with long spikes as well as tie straps at regular intervals.
Though the process of doing earthbag can seem labour intensive, as a crew gets practiced it goes very quickly. Because there is no requirement for advanced formwork, it can actually be very competitive with forming and placing concrete. With a day’s practice, our crew was producing over 1.5 feet of finished bag per minute! The beauty of earthbag is its simplicity. Bag material and fill as well as all the required tools can be found in almost any location in the world, and the strength and durability of earthbag foundations (or entire buildings) is remarkable. Bag on!”
More at the source: Endeavour Centre.org
4 thoughts on “Earthbag Foundation for Floor System”
Ah. That wasn’t clear to me. Now it is. Thanks.
Most soils will compress under the weight of a full sized earthbag wall. Settling will cause the plaster crack apart, etc. So obviously strong foundations are critical.
In this application the bags are internal walls. And, as you can see in the photo they’re resting on a bed of gravel. So this is not a typical case. Most earthbag buildings will benefit from a rubble trench foundation. Earthbag walls are very heavy. Rubble trenches are great for carrying heavy loads like this.
Brilliant! Why didn’t I think of that? There’s no need to dig a trench for extra drainage really, is there? The gravel will simply let the water wash through, and the bags are more than strong enough by themselves, without being embedded in the ground. Thanks for sharing!