[GSBN] Exterior plaster sealer?

[Tim Owen-Kennedy]

When we built Ridge winery we built a test wall and finished it with lime
plaster over earth plaster. Then we applied 16 different finishes and tested
for cleanability (ability to take a light pressure washing or scrubbing) and
checked behind the plaster, 2" in, and 4" in from the backside which was
unplastered. Silane/siloxane was obviously the best but the oil entrained
limewash was more than adequate. We didn't do long exposures to the hose but
hosed the whole thing down three times after the pressure washer test. the
whole thing was too subjective and sloppy of a test to write up but I can
try and find my notes if anyone cares.

We used 5% linseed oil by volume in our limewash, bended thoroughly and
repeatedly. We were hoping this small volume wouldn't decrease vapor
transference too much. Though, since this was the interior against the high
humidity barrel storage room, we wanted to decrease it some. 10 years later
there are no challenges and I just went back to do maintenace and checked
all the walls I could.

Tim

On Fri, Jan 21, 2011 at 1:36 PM, Tom Hahn <tomhahn at econet.org> wrote:

> There's that expertise I knew would come to the fore from John... :-)
>
> I misspoke in naming only "siloxanes", but most, if not all of what we have
> used, including most of Enviroseal's products, are blends... and yes, I
> agree with the need for a blend in alkaline compositions...
>
> Thanks for catching that, John!
>
> And, under the conditions described by Darrel, I also think the rainscreen
> design (however it is best practiced...) is worth having as a backup plan,
> in if an extensive retrofit is necessary.
>
> Tom
>
>
>
>  I agree : siloxanes are great. But silanes are more tolerant of highly
>> alkaline substrates and hence why I recommend the blend (not sure how much
>> lime is in the mix).
>>
>> John Straube
>> 519 741 7920
>> Sent via BlackBerry
>>
>> -----Original Message-----
>> From: Tom Hahn <tomhahn at econet.org>
>> Sender: GSBN-bounces at greenbuilder.com
>> Date: Fri, 21 Jan 2011 07:33:02
>> To: (private, with public archives) Global Straw Building Network<
>> GSBN at greenbuilder.com>
>> Reply-To: "(private, with public archives) Global Straw Building Network"
>> <GSBN at greenbuilder.com>
>> Subject: Re: [GSBN] Exterior plaster sealer?
>>
>> Ultimately, I'll defer to John's expertise with them, but we have
>> also had good experience with siloxanes... admittedly not under such
>> severe conditions as you describe, Darrel.
>>
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-- 
Tim Owen-Kennedy, Owner
Vital Systems, natural building & design
P O Box 751, Ukiah, CA 95482
www.vitalsystems.net
888.859.6336
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