Thursday, April 9, 2009

Earthquake Resistance and Energy Conservation

A few other contributors have already posted about concepts that have been put forth by architects relating to green building. For example, William McDonough's work with Cradle to Cradle and use of appropriate, sustainable and sensible materials in architecture. While McDonough is relatively high profile in the architecture world, many many others have done similar work following themes of new urbanism, vernacular architecture and novel materials.

Apart from these efforts though, I'm reminded of a construction method which has always had a small following but may now become more prevalent, particularly in earthquake-prone developing countries. Straw bale construction takes the space in walls normally reserved for sprayed insulation, rolled batts or rigid insulating boards and fills it with stacked straw bales. The straw bales provide far superior insulation to engineered products and use what is a relatively low value, recyclable material. Straw bale homes are not inherently more expensive than standard platform frame construction, except that contractors familiar with the construction method may be harder to find and more expensive. And except for the thick walls and deep sills, the interior of a straw bale home is no different than any other home. There appear to be advantages to straw bale buildings beyond their impressive insulation capabilities. Tests performed by structural engineer Darcey Donovan at University of Nevada, Reno have revealed that straw bale buildings are also excellent at withstanding earthquakes. Donovan's efforts are focused on Pakistan and their rebuilding efforts after the earthquake in Azad Kashmir in 2005, however, her results and subsequent reconstruction and development program might be replicated to great benefit in other areas devastated by earthquakes, particularly agricultural regions. For example, the recent earthquake in Italy is in a region where local (or neighboring state) sources of straw exist and straw bale construction might be a sensible approach to rebuilding efforts. Areas here in America with particularly hot weather and that are earthquake-prone are also (often) centers of agriculture and would be excellent places to encourage new development with straw bale methods.


amyscholze said...

This article is interesting, because while there always seem to be many questions about which is more enrgy efficient, faced or unfaced insulation, this puts a new spin on isulation energy conservation. My first thought was where is this method most popular and practical in the world? I figured the best bet would be area's of highest straw production (like Nebraska in the US and other countries?) but that number was hard to come buy. Although I did read that most of teh houses built with straw bale construction are locally supplied, which ties to the "food mile" discussions we have had of late.

As I continued to think about this technique common questions came to mind, like: How fire resistant can straw insullation be? And what about dust and mold? Not only would the insulation be spoiled, but talk about allergies...ugh.

It turns out, the original website refernced in this post also answers many of these questions and more.
To summarize, as long as the plaster coated walls are properly constructed around the bales, the straw should be water free and thus mold free. However, if the inside walls ever get wet from fire sprinklers, the walls would have to come down and be rebuilt. I am still not completely convinced, especially in areas of high humididty, but I read in more than one place, that rice straw has incresed resistance to decomposition because of its high silica content. Also, there are no seeds in any straw bale construction types so that apparently eliminates natural allergens.
Regarding their fire resistance, the website claimed that the walls passed standard firewall assembly tests, and actually took longer to catch fire than walls insulated by fiberglass or foam. Anyways, everything I've said here and more can be found either in this article or within the website of this article.

Miguel Baca said...

I read your post and I got interested just by the question: What if it is too late?
I recently found this news in the NYTIMES about the OREGONIANS from OREGON, sorry about to be redundant. In this note, they talk about how some families are trying to shrink their per-capita consumption by 80%. This idea might achieve the Swiss project called 2,000 Watt Society.
If it is not too late, there could be an option to save this World and build a greener society for future generations. This 2,000 Watt projects believes that “The emissions of the future rich must eventually equal the emissions of today’s poor” (Bill Chameides).
I have tried to find more about this project and basically it seeks to achieve a level in which” each person in the developed world would cut their over-all rate of energy use to an average of no more than 2,000 watts by the year 2050, without lowering their standard of living.” (Swiss Federal Institute of Technology). As Elizabeth Kolbeth mentioned in her column in the New Yorker , this two thousand watts is approximately the current world average rate of total energy use. This compares to averages of around 6,000 watts in western Europe, 12,000 watts in the United States [1], 1500 watts in China, 1000 watts in India, and only 300 watts in Bangladesh.
I think it is an achievable amount but we must understand that the developing countries need to consume more energy than they do today if they ever want to be fully developed. Countries like Brazil or Mexico which today have low greenhouse emissions and per-capita energy consumptions around 1,700 kw, they will increase their energy demands to meet their development. So in this case, governments should encourage the use of cleaner technologies without jeopardizing their development.

Work consulted:

Zoe said...

I actually participated in the raising of a straw bale house in Austin a number of years ago. For those who are interested, check out volunteer and workshop opportunities at Design~Build~Live