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Re: GSBN:test results

Probably an easily dismissed question re: waterproofing earthen plasters, but I've often wondered whether the siloxane-based sealers that have been promoted for cement stucco would be applicable. Obviously they stray from the purist ethic, though I wonder if anyone has tested these sealers, noted for their gore-tex-like effect of keeping liquid moisture out without overly diminishing vapor permeability?

I would also like the test results forwarded to my personal e-mail account if possible (anovelli@aol.com), as I can't seem to find them on our main subscription here.

Many thanks!

Tony Novelli

Howdy, baleheads -

There has been a moderate amount of clucking in the international strawbale
henhouse over the recently published (and perplexing) test results.

Lonesome Rob Tom was first to sound off, sharing his usual rants via
satellite hookup while herding mooses across the frozen Canadian tundra . .
thengya, Rob, thengyaverramuch

Bill Steen chimed in from up in the Patagonian mountains above Tucson,
stomping around the desert with a five pound sledge, whacking every lump in
sight, muttering under his breath like Gabby Hayes about gol durn ceeement
plasters, Athena and the children huddled terrified inside the deadbolted
house . . .

And John Glassford, our John the Baptist of earthen plasters, honey and
locusts dripping from his chin, a wild glint in his eye, came the most
directly and clearly to the point by writing:

" . . . Which begs the question, if cement/lime mixes rely on certain
temperature and moisture levels to cure and earth/straw does not, and
earthen renders are proving not quite as strong, but well above California
code limitations, why not use earth as a preference?  By this I mean look at
ways of getting earthen/sand etc. render premixes onto the main stream straw
bale building best practice list . . . Makes so much sense and once we have
the water proofing angle sorted out and how best to keep moisture out then
we are miles in front from all angles.  Especially as we know are able to
pump our earthen mixes on without any problems from first to last coat."

I completely agree, and we will be doing a lot more testing of earthen
renders for structural and moisture properties.  I would also add that we
need to identify, for durability, not only how to make earthen plasters shed
water, but how to keep them from flaking and dusting too much.

(I can hear you all scoffing   "Limewash!  Duh!" , and I doubt we'll come up
with anything better or different, but you never know.)

keep those cards and letters comin', folks.  We're listening.

Bruce King, PE
Director, Ecological Building Network
209 Caledonia St.
Sausalito, CA 94965
(415) 331-7630
fax 332-4072

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