We are in the Sahel, and are considering building our house with earthbags. This would not be our first build, as we've done some round (non-domed) earthbag houses in the past. However, this would be by far the most ambitious build to date. We would love some insight from experienced builders or engineers.
Although we love curved walls in some contexts, for this house we opted for straight walls. We chose an octagonal shape for the building, which consists of two separate structures and a covered porch surrounding a courtyard, all connected by a roof. The courtyard and long (2m) eaves are intended to help passively cool the house in our tropical climate.
On the right, light brown indicates lofts, dark brown 2nd story
In designing this layout, we kept in mind recommendations we read in Hunter & Kiffmeyer's book, specifically that straight structural walls
should be buttressed every 5.4 m. (I've even heard 6 m. elsewhere)
However,
this book by Patti Stouter says to keep your non-buttressed straight walls to 4 m. or less.
Meanwhile,
this page on Kelly Hart's website gives even more stringent guidelines for straight walls: buttresses every ~3 m.
Who's right?
Wherever possible, we are using interior earthbag walls to provide extra support. On the living/dining/kitchen area, which has high ceilings, and on the guest apartment, which is two stories tall, we plan to pour a reinforced
concrete bond beam around ceiling height. We've allowed a meter from all corners to any windows and doors, and kept these openings no wider than 1.2 m (except for a few interior arches, which we plan to reinforce by adding some cement to the earth in the arch, and a few windows that are capped by the abovementioned bond beam). All corners will also get rebar pins for added strength.
For those of you with
experience with these kinds of buildings - are these measures sufficient? What else should we be considering? Do you see any red flags? Are we being over-ambitious trying to build at this scale with earthbags?
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