[GSBN] Failures due to moisture migration in bale walls

[Chris Magwood]

Hi all,

I'm working on a "defense" of the vapour permeable nature of straw bale 
walls for a building code for an alternative solutions application here 
in Ontario.

The building department is particularly concerned about the lack of a 
vapour barrier in the system (again!). I'm pulling out all the usual 
test documents and building science theories to help make our case.

But I'm interested in knowing if any of you out there have actually 
encountered a bale wall that has failed due to moisture migration 
through the wall, especially during the winter. I've certainly seen some 
damage done by consistent exposure to rain, or leaky roofs, or other 
bulk-water intrusions, but I've never seen a moisture migration failure. 
If that has been the general experience of this list, with its wide 
variety of climates and building styles, then that would seem to me to 
make a good evidence-based defense for this.

And if you have seen such a failure, I'd be interested in knowing about 
the suspected (or known) causes, the conditions that led to this 
failure, and whether or not the situation was able to be remedied.

I don't need everybody on the list to respond... perhaps only those 
who've seen examples of this type of failure. If the list is silent on 
this, I'll take that to mean that this really hasn't shown itself to be 
a major issue, and will say so in my AS application.

Thanks all!

Chris

-- 
Chris Magwood
Director, Endeavour Centre
www.endeavourcentre.org