[Strawbale] Mycotoxins (GSBN Digest, Vol 35, Issue 20)

[RT]

On Thu, 24 Mar 2011 13:00:02 -0400, <gsbn-request at greenbuilder...> wrote:
> Date: Thu, 24 Mar 2011 07:56:02 -0400
> From: carolatkn
> Subject: [GSBN]  Mycotoxins

>
> I recently met a young couple wanting to build a new home on their  
> family farm in south west England. They had been told by their architect  
> that they should discount straw bale immediately as they would be  
> certain to die from exposure to mycotoxins!

> My initial response is that if the straw is baled and kept dry there  
> will be few moulds anyway and crack free plaster would prevent any that  
> were present making their way into the living space.

[BIG <snip>]
for full text of message and thread see:
http://greenbuilder.com/pipermail/gsbn/2011q1/001379.html

Sometime within the past 10 years (+/-) the City of Gatineau (in the  
Province of Quebec, Canada (just across the river from Ottawa of which the  
former City of Kanata is now a part)), wanted to enact a by-law to ban the  
use of straw bales for making buildings in that city.

The City's reason for wanting to do so was because of moisture-related  
problems with at least one SB house (a two-storey dwelling, exterior  
plaster fully exposed to rain wetting) in that city.

A woman who spent time in that house and another SB large building (with  
known wet SB issues) elsewhere in the province of Quebec reported that the  
buildings made her sick.

Don Fugler was one who kept files on these before he retired from CMHC.  I  
don't know if Don was able to acquire any funding to have forensic testing  
done on the affected buildings as he did for the report:

    "Pilot Study of Moisture Control in Stuccoed Straw Bale Walls" (June  
1997)

where the walls and floors of SB buildings that had been occupied for ~10  
years were cut into, straw samples taken/inspected and moisture paths  
identified.

That report, which includes nice colour photographs of mould-deteriorated  
straw should still be available from CMHC.      http://cmhc.ca/

If not, I'd consider scanning it and putting it into a PDF if sufficient  
demand warrants (and if CMHC gives its permission).

As with any other moisture-susceptible cellulosic material that is allowed  
to get wet and not provided with the means to dry properly, one can expect  
microbial activity to occur.

It was mentioned by a senior bureaucrat at Health Canada (at least 15  
years ago) that straw is an ideal host for Stachybotrys atra   
(Stachybotrys chartarum) , a black mould that was a prime suspect in  
infant deaths ( pulmonary hemorrhaging).

True, SA needs humidity levels of ~90% in order to develop but that would  
not be out of the question in a SBH built in a Cold Climate region where  
insufficient attention was paid to air-sealing and/or keeping rain off of  
exterior plaster and/or faulty flashing details and/or about a half dozen  
other reasons.

Bottom line: The fears expressed by the Brit architect may be over-stated  
but not completely off-base, probably a hysteria borne of seeing bits and  
pieces of messages like this one, out of context.


-- 
=== * ===
Rob Tom
Kanata, Ontario, Canada
< A r c h i L o g i c  at  Y a h o o  dot  c a >
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