permaculture

[Robyn Francis <erda@nor.com.au>]

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.
I have used earthbrick walls (on top of several courses of fired bricks on
top of the foundations) and earthbrick floor in my training centre but only
for the central training room - this is protected from sun and rain by
surrounding rooms and 15ft wide verandas. The thermal mass becomes a heat
sink on summer days and cools down over night, the veranda roof on the
winter sun side has a small section of clear roofing for winter sun to come
in the glass doors for winter daytime heating. The ceiling/roof is very high
and well insulated with a clerestory of louver windows for ventilation.

The bioclimatic building mantra for hot, humid, high rainfall climates is
insulation, ventilation and shade, and avoid thermal mass on external walls
(selective internal use ok). Good drainage and damp coursing absolutely
essential.

The only successful exposed earth wall structures in this climate zone seem
to be mechanically compressed rammed earth with 10% cement in the mix, even
so they need big overhangs and solar screens to avoid excessive heat gain.
I'm experimenting with bottle walls set in a mix of 3 parts earth: 2 parts
sand: 2 parts cement - they're holding out so far in the weather. Another
material that copes with this climate is 'saw-ment': sawdust, sand and
cement (3:2:1) packed like pressed earth between the timber frame studs and
nogs - need 4 inch studs for extra thickness. Many houses in this areas are
using colour-bonded corrugated roofing iron for weather-exposed external
wall cladding with good insulation then plasterboard or timber internal wall
lining. 
Could write more but other work calls...
Ciao
Robyn




On 1/02/10 4:15 AM, "Udan Farm" <udanfarm@yahoo.com> wrote:

> HI Folks,
> Reading about Quail Springs and their buildings, (I've been there by the 
> way,
> and it's really a great example of permaculture in dry climate) I've been
> wondering if ANYONE knows ANYONE who has previously already BUILT any kind 
> of
> earth homes-cob, in-ground, earthship, cordwood, etc. homes in the 
> SOUTH...I'm
> talking HOT, HUMID, buggy, HUMID southern USA?
> I ask because a lot of folks are looking to me and my husband, as 
> permaculture
> teachers, asking questions about building something from earth that doesn't
> cost 200k, and I'm of the mind that those big thermal mass things connected 
> to
> the ground DO NOT work well in the humidity. It gets cold and hot here,
> sometimes with about a 40* range in one day, add the humidity and the walls
> (even on a well insulated stick built house) SWEAT something aweful, and
> books, rugs, fabrics, clothes and shoes go quite moldy.
> I'm fond of the Cracker style house-up off the ground, wide porches, lots of
> windows, high ceilings, and a cupola on top that opens.That works for FL and
> central GA but even up into the mountains, the ONE building I know of that's
> about 7 years old-made of cob and sitting on the ground is MOLDY smelling 
> the
> minute you walk in it. And I know everyone knows that the answer is not HVAC
> running 24/7/52...
> I would love to hear you thoughts on that subject and if you know anyone 
> with
> an older thermal mass/earth house I could ask these questions of...
> Thanks!!Isabel
> 
> 
> 
>       
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