[GSBN] Exterior plaster sealer?

[Tim Owen-Kennedy]

Sorry for the slow reply, I'm back in Rural Haiti - this time with Bruce King.

John, and...

All I know that I know is that there is a tradition of adding oil to
both earth and lime plasters in Europe or so I've heard from 5
sources. I have also heard from someone who slaked lime in Portugal
that they slaked it with oil (lard if I remember right). that is what
inspired us to give it a try. and we've tried it several times but
that's still not a certainly known

What I remember from John Straube was that the oiled earth or lime
plaster dramatically decreased permeability but that mixing a small
amount in (10% or under) didn't seem to effect the vapor permeance
appreciably. But I can't say weather this was a definitive or
speculative response.

Tim "knowably off" O-K

On 1/24/11, John Swearingen <jswearingen at skillful-means.com> wrote:
> Tim,
>
> I recall seeing something a long while ago, perhaps from John Straube, that
> indicated that the addition of linseed to the plaster mix had little value.
>  Am I misremembering, and that is something we know that we know, or is it a
> well-known unknown.  What do you know?
>
> John "UnOwned" Swearingen
>
>
> On Sun, Jan 23, 2011 at 6:15 AM, Tim Owen-Kennedy <timok33 at gmail.com> wrote:
>
>> 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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>>
>
>
> --
> John Swearingen
> Skillful Means Design & Construction
> 2550 9th Street   Suite 209A
> Berkeley, CA   94710
> 510.849.1800 phone
> 510.849.1900 fax
>
> Web Site:  http://www.skillful-means.com
> Blog:         https://skillfulmeansdesign.wordpress.com
>


-- 
Tim Owen-Kennedy, Owner
Vital Systems, natural building & design
P O Box 751, Ukiah, CA 95482
www.vitalsystems.net
888.859.6336