Earthbag Building in the Humid Tropics: Simple Instructions by Patti Stouter is a 27-page, step-by-step PDF guide to building with earthbags in these demanding climates. It is well thought out, quite informative, and useful as a basic introduction to the concept of building with earthbags.
She begins with a general introduction, and then moves on to a discussion of stabilizing earth as a construction material and the use of earthen plasters. She points out that “small houses can easily be built strong enough without cement or bitumen. Tests have shown that a careful balancing of the range of particle sizes in a soil may improve strength more than added cement. Earthbag walls seldom need additives to give extra stability.”
The step-by-step description covers: soil tests, materials, layouts, footings, laying bags, base courses, openings, bond beams, roofs, floors, and finishes. Patti puts forth some general principles for earthbag building in humid climates:
➔ Use as much lightweight gravel as you can afford for cooler, less sweaty buildings.
➔ Use as little wood or metal as possible, to avoid rot and termites.
➔ Use plan layouts that are stable, with curves or frequent piers or buttresses.
➔ Make sure rainwater flows away from the bases of all walls.
➔ Use a vapor barrier below the floor and between any concrete and earth.
➔ Provide a waterproof base course at least 60 cm high.
➔ Criss-cross bag courses at piers and corners.
➔ Provide wide roof overhangs (1.5 m is good).
➔ Test exterior finishes for performance.