Let’s take a brief respite from castle plans, shall we? Our website traffic has hit another major spike and so I’ll take this opportunity to summarize some key facts about earthbag building.
A few quick facts:
– Successful completion of an earthbag/strawbale shake table test in Nevada applied forces that surpassed that of the Northridge quake in California.
– Seismic tests in California showed zero deflection on earthbag domes with forces that maxed out the testing equipment.
– Engineer and code approved earthbag designs are now available for seismic and non-seismic areas through Precision Structural Engineering, Inc. This had been a major barrier in the past, and we’re glad to see this service on offer.
– A master’s degree thesis showed earthbag walls have 10 times the bearing capacity of stud framed walls.
– Sand bags are the material of choice for storing ammunition in war zones due to their ability to absorb blasts (if they’re strong enough for this, they’re definitely strong enough for housing).
– Around a dozen earthbag projects are taking off in Haiti. Some of have been completed and the groups involved have decided to build more earthbag structures.
– Earthbag is comparable to rammed earth, which can last for thousands of years. See Ancient Rammed Earth Structures.
– Earthbag consists of compacted earth, which has now been shown to be resistant to 50 caliber bullets.
– Compressed earth walls withstood impact testing from a black powder cannon that’s comparable to forces from F5 tornadoes.
– There are various ways of stabilizing earthbags and/or filling lower courses with gravel to make them extremely resistant to water damage, including floods.
– For cold climates, bags can be filled with insulation or earthbags can be covered with a layer of insulation.
– A Federal Highway Administration report estimates the half life of polypropylene bags (sand bags) may exceed 500 years in benign environments.
– Earthbag is faster and more efficient than building with adobe, cob, rammed tires and rammed earth.
– Building with sand bags is around 250 years old if you include the original burlap structures built by militaries.
– Countless millions of poly sand bags are used every year to hold back floodwaters because they’re simple to use and effective.
– An earthbag wall passed a recent wind test with out-of-plane dynamic pressures up to 30 psf and quasi-static pressure up to 60 psf.
This list barely scratches the surface as far as identifying all the benefits of earthbag building. There are now over 730 blog posts available on every aspect of building with bags — foundations, plastering, domes, greenhouses, rootcellars, you name it, it’s here. Every topic can be searched from the search engine near the top of the page. You can also search this blog and our main site (which is by far the largest repository of all things related to earthbags) with our new search engine at EarthbagBuilding.com.