Domes are very strong and perhaps the best option for many areas. However, in rainy climates they are prone to leaks. (Domes originated in desert regions, after all.) In high rainfall areas, roofs with overhangs to protect walls are recommended. Roofs need to be very well built with hurricane tie downs. This is the weakest link in the design because roofs are vulnerable to wind damage, so study up on the specialized building techniques available.
Consider something like this Sand Castle house built by Steve Kemble and Carol Escott. Round, hexagonal or octagonal shapes are all good choices because wind will flow around the building. Same idea applies to the roof.
One big consideration is building on grade versus building on piers off the ground. Try to find some high ground and build on grade (or 1’-2’ above), since this will be stronger and less expensive.
Bag fill: The crushed coral/sand mix used on the Sand Castle is a good choice if available locally. Road base is more commonly available and can be stabilized with lime. Road base is the clay/gravel mixture used to build roads. It’s cheap, plentiful and very strong. And with lime added, walls become virtually waterproof and almost as hard as concrete.
One story structures reduce exposure. Design in fast mounting storm resistant window shutters. Keep roof overhangs to a minimum, maybe 24″, to help prevent uplift.
So in summary, a properly designed earthbag structure is the strongest sustainable building system that I know of. The only thing stronger is reinforced concrete, and that’s not sustainable.
I have numerous plans that could be adapted for hurricane and tornado prone regions at Earthbag House Plans.
These plans are available through Dream Green Homes. I modify plans at no extra cost to meet your codes.
Hi there Owen,
Thank you for keeping up with your blog, it’s been very helpful!
I live in Malabar, Florida and my partner and I are looking to build an Earthbag home. We’re young and inexperienced when it comes to trying to figure out how to “build to code”. Do you have any pointers on how to figure out how to present our building plans to get approved? Also, I can’t seem to figure out how to find any contractors in the area. Do you have any connections or know who might?
Thank you for you time Owen!
Florida and California have some of the strictest codes in the world and are the most difficult and expensive to work in. Lots of people ask me where they can find earthbag contractors so apparently there aren’t any available. To meet rigid codes you need to thoroughly understand them as a contractor would. For the engineering we recommend Structure1.com. They can get my plans approved. But first you need to find a contractor.
I am considering building in the Bahamas. Do you have any more information on this house or any contact information for the owners? Thanks.
Earthbag building is the strongest, most practical building method for the Bahamas and other similar areas. See this example that’s withstood numerous hurricanes:
http://www.earthbagbuilding.com/projects/sandcastle.htm
Our blog here has lots of articles about building disaster resistant housing.
hi ! thanks for the great posts. is there any earthbag solar sauna workshop?
Earthbag saunas: Great idea! Haven’t heard of this yet. You could be the first.
We built an earthbag sauna as a pilot project prior to starting construction of our new home. It’s a wonderful little building! http://www.facebook.com/pages/New-Brigden-Alberta/Canadian-Dirtbags/128912733998
Looks great and good idea! I think this will make an excellent addition to our Projects page at http://www.EarthbagBuilding.com. I’ll turn this over to Kelly.
The blog is a nice start. I wonder if any part of the structure can be earth bermed to reduce exposure and increase mass.
Yes, berming earthbag structures is a great idea. Many of my plans at Earthbag House Plans are earth-bermed or earth-sheltered. The main requirement is adding 1-2 layers of 6 mil poly between the earthbags and earth.