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Re: Re: GSBN:Re: Danny Buck's moisture NM

Hello from Portland - a wetter place than my customary climate (Tucson),
where I am attending the USGBC Greenbuild conference.

I just need to reiterate a point I've made many times on this subject -
that is the impossibility of keeping moisture out of these assemblies. If
we can't keep moisture from getting into double glazed windows - two
pieces of glass separated and sealed with the highest tech materials we
can invent, built in a factory and put into a frame - why would you think
we could build an assembly in the field, with the variability of
materails, designs, workmanship and all that happens to those assemblies
over time and water won't get in? It will. Take that as your base
assumption and make sure it can get out. I can't say this strongly enough
- things get wet, make sure that the drying capacity is stronger overall
than the wetting mechanisms...

Gotta go...


>From:  TLSEditor@...(Chris Magwood)
>Sender:    GSBN@...(GSBN)
>Reply-to:  GSBN@...(GSBN)
>To:    GSBN@...(GSBN)
>>My feelings these days are that under no circumstance should we allow
>>moisture to enter a straw bale wall in any form from the inside or the
>>outside.  Why take a chance on the moisture finding it's way out of a
>>wall?  Therefore I am of the opinion that we should make sure that
>>moisture in vapour or solid form cannot get into a bale wall.  Therefore
>>we should treat the finished coat of render accordingly and use methods
>>and materials that will give a water proof wall from BOTH sides.
>I think John raises an interesting issue here. I've always stuck by
>the breathable argument, and have seen some surprising examples of
>drying taking place this way after significant soakings. But I, like
>John, don't want to leave it to this process entirely.
>I have lately been experimenting with silicate paints (from Eco-House
>in New Brunswick). They claim an excellent water repellancy (is that
>a word?) and little effect on breathability. I can attest to the
>repellant qualities... even on earthen plasters water will bead and
>roll off. But does anybody know for sure if the breathability is as
>good as is claimed? If so, I think the silicate paints are something
>that could be widely promoted for straw bale. They seem to be
>relatively non-toxic (again, based on manufacturer claims) and
>created with natural materials, the colours are excellent, the cost
>is reasonable... Seems like it could be an excellent solution to one
>of our biggest concerns, and an easy one too, if it works like it
>seems to work.

David Eisenberg, Director

Development Center for Appropriate Technology
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