[Strawbale] [FWD] rainscreens, straw decay

RT ArchiLogic at yahoo...
Sat Feb 28 08:35:02 CET 2009

========= Forwarded from SB-r-Us AYahoogroups =======


I’m a graduate student at Nihon University researching the
interstitial hygrothermal environment of straw bale buildings in Japan.  I  
several questions on a couple of different topics.

1.           I’m monitoring eight straw bale buildings in Japan.
Generally, interstitial humidity and straw moisture content increases  
the exterior.  Comparing indoor and outdoor humidity levels suggest that  
than exfiltration or diffusion of indoor moisture, external moisture is the
primary cause of interstitial moisture.  I’d like to investigate the
influence of rain screens on the interstitial environment.  It may be too  
to build identical straw bale structures, but I could build two or more  
bale walls protected from any unintended moisture.  The structure of the  
would be identical except that one wall would have a rain screen.  I could
spray the walls with a measured quantity of water (in liters per minute)  
monitor interstitial relative humidity and straw moisture content.
The recent conversation on ventilated rainscreens has been helpful.  Thank
you.  I’m looking for construction details of straw bale walls with rain
screens to share with an architect.  I’ve found rough wall sections in
King’s “Design of Straw Bale Buildings”, Minke’s “Building with
Straw”, and Chiras’ “The Natural House”.  If any one could provide
construction details or detailed photos, I’d be grateful.  (Thank you John  
Australia and André in France for the descriptions.)

2.           I removed samples of straw from two straw bale structures
at our research center.  Samples of straw were taken from around five
temperature and relative humidity sensors.  One structure has been  
for six years, the other for two years.  The condition of the straw was
analyzed for mold and decay.  63 times magnification revealed fungal  
hyphae in
what was to the naked eye clean straw.  A Yamaco MT-700 C-N Corder was  
used to
measure total carbon concentrations.  As fungi digest straw, they consume  
carbon in the straw and give off carbon dioxide.  The percentage of total
carbon in the straw should, in theory, decline as the straw decomposes.   
concentrations were compared with new straw from 2008 grown and dried at  
research center.  As expected, the straw from around sensors with a  
history of
high relative humidity had the lowest carbon concentrations.
               For those who know more about this then I, is total
carbon a good measure of straw decomposition?  What other tests could be  
to determine the extent of straw decomposition without samples of the  
straw at the time of baling or building?  I was considering comparing  
carbon isotopes C12 and C14.

3.           I’d like to submit a paper to the Journal of Asian
Architecture and Building Engineering, a peer reviewed Journal sponsored  
by the
architectural associations of Japan, China, and Korea, by April 8 for
publication in November.  Would anyone be interested in helping me with a
statistical analysis of the carbon experiment described above?  Last year I
received help with a paper from a couple of people on this list.  Many  

Kindest regards,
Kyle Holzhueter
Nihon University
Graduate School of Bioresource Sciences
Architecture and Regional Ecological Design Studio
1866 Kameino Fujisawa-City Kanagawa-Prefecture 252-8510

TEL/FAX (81)466-84-3364


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Rob Tom
Kanata, Ontario, Canada
< A r c h i L o g i c  at  ChaffY a h o o  dot  C a >
(manually winnow the chaff from my edress in your reply)
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