[permaculture] Question about Earth Homes, thermal mass and humidity

katey culver newtribe at hughes.net
Wed Feb 3 18:48:53 EST 2010

Hi Robyn,
Are you a builder or architect?  I am wondering how extensive your
experience is.  I am partner in the architect/design firm Ecoville
ArchiTechs.  We live in the Southeastern US and promote natural building
methods.  Since 1994 we have helped over 35 clients in 9 states build with
straw bales.  I have not found it to be true what you say about humidity and
straw  bale homes.  Humidity is not a problem.  Moisture is a problem if it
gets in your walls, just like with any building.  You detail to prevent it.
In our designs we also add a drainbed under the straw in case the bathtub
overflows.  We use a lime/clay plaster which also performs well in our
region.  And of course the Burritt Mansion in Huntsville AL is straw bale
built in 1936, still in use today as a public building.

We have not yet had a client who wants to build cob but we'd welcome it.  We
have worked on many cob structures in the area that are doing fine but they
are not conditioned living spaces.  Some of these are going on 15 years; so
far so good.


Katey Culver

On Sun, Jan 31, 2010 at 9:18 PM, Robyn Francis <erda at nor.com.au> wrote:

> Hi
> I live in a similar climate to SE USA: hot, muggy, humid and big rains in
> summer and big temperature changes from day to night so condensation can
> also be an issue. Here we need to be very careful using earth or strawbale
> construction. I've seen numerous earthbrick/cob structures in this area
> simply erode away with torrential rains, and know of issues with strawbale
> buildings with humidity entering through the render and the straw
> decomposing and becoming an ant metropolis.

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