[GSBN] Failures due to moisture migration in bale walls

[Jacob Deva Racusin]

Chris,

We've been moisture testing bale walls in the cold climate of northern 
US for over a decade, and have yet to see any damage primarily as a 
result of a lack of interior vapor barrier and resultant vapor 
migration. We have seen issues as a result of a cold-side vapor barrier 
- in the form of pure cement stucco - but that's it. I'm happy to talk 
more off-list if I can help supply particular materials or informational 
sources. If it helps with documentation, we produced a report based on 
commissioning of a series of buildings we built that discusses this and 
related durability issues, which you can download off our website here: 
http://newframeworks.com/home/media/#report

Best of luck,
Jacob

On 6/27/15 11:35 AM, Chris Magwood wrote:
> 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
>

-- 
Jacob Deva Racusin
Co-Owner
New Frameworks Natural Design/Build

Author, The Natural Building Companion
Chelsea Green Press, 2012

(802) 782-7783
jacob at newframeworks.com
http://www.newframeworks.com