This small structure is the ECHO Asia Seed Bank’s earthbag house that is nearing completion. ECHO promotes community-based seed sharing and saving. It is also part of their mission to recommend appropriate ways for communities and organizations in the developing world to better store seeds.
James (ECHO Asia intern) and Lue (Assistant Seed Bank Director) were trained in earthbag house construction by Engineering Ministries International (eMi). To prevent the invasion of surrounding warmer air (the seed bank is located in a tropical/sub-tropical region), a small door with a foam interior and a thick but light ceiling composed of sacks filled with burnt rice husks were installed. And to keep costs low, almost the entire structure was made from local, cheap materials, including a roof of fan palm thatch.
Data loggers will be installed to record the interior temperature and relative humidity. These will be compared with outside readings over a period of one year. So we look forward to reporting on the long term results of the modification of temperature by the earthbag house and the potential of such structures for community-based seed storage in the tropics.
See sustainabilityquest.blogspot.com to read the entire article.
EMI has been recommending earthbag in some different projects lately!
I’d like to hear a little more about the burnt rice hulls. I’ve been concerned about rice hull insulation being invaded by mice. Rice hulls are naturally more mold resistant than most natural insulators, but when burnt are they more so?
Very clever idea. This has lots of potential.
To keep the house cool inside it will really help to build in the shade as much as possible and build the roof so the sun never shines directly on the earthbags (which will soak up the heat and radiate into the house).
Add plastic sheeting under the floor (tamped earth?) to prevent wicking of moisture. Use gravel bags in lower courses to prevent wicking of moisture. Build on high ground to reduce risk of flooding. You can add borax to the soil to deter termites and/or vetiver/clay in the bags. http://www.youtube.com/watch?v=xSN9mOrVU1A
Vetiver Network International has info about termite resistance of vetiver: http://www.vetiver.com/
Plus, vetiver would provide additional insulation. It’s worth testing.
I’m interested to see how the seed bank compares to our earthbag roundhouse that’s 8 degrees C or 15 degrees F cooler inside than outside on the hottest days.
Owen, you were very helpful in getting us set up. James the intern (pictured) who provided most of the effort to construct the house was in touch with you months ago.
The data loggers are logging away. I stepped into the structure recently on a near 40 degree day and found the inside refreshingly cool.
The burnt husks seem to be working well and no mice (yet). But the bamboo inside wasn’t treated and did get termites. So in handsite, borate treatment would have been good.
I like your suggestion about the plastic sheet.
We’ll be reporting on the recorded temp/humidity data in early 2013.
Glad to help. Thanks for the update. How cool is it inside when it’s 40 degrees outside?