[Scpg] Water-proofing for mud/cement wall in a greenhouse?

[Fitzsimmons, Mark A PWR]

Can't you plaster it and then paint with an exterior latex? Or will that
peel to quickly in the moist environment? One concern I'd have is if you
waterproof the inside and outside well, and you get a leak somewhere,
you might get rotting inside the wall and never know.

I have had great success with CIM industrial membrane in a variety of
situations. I recently waterproofed an old rusted steel tank with CIM
1061 (UL listed safe for potable water).

http://www.cimind.com/

It makes an impervious, safe water tight polyurethane barrier.

It is really messy stuff before mixing and cure, and the fumes prior to
cure are toxic, so find someone who has worked a lot with epoxy or
fiberglass to help you install it, and make sure you have the proper
safety equipment (activated carbon chemical respirator, fresh air (fan
or shop vac) and follow the washing instructions after letting it sit a
week. 

It's expensive, but less costly than epoxy. I used 4 gallons for a 6'
dia x 6' tall tank. You have to work fast with rollers, as it only has
about a 20 minute working time before you can't effectively roll it
anymore, and a trowel or squeegee action is more effective.

For lower cost, you can somehow stitch a thick polypropylene sheet to
the inside of the structure and only seal the seams and punctures with
the CIM, however this will not last nearly as long, as the plastic sheet
will often begin to come apart from sunlight in just a few months, where
the CIM will not.

You might also try some brands of polyurethanes. The best one (I've used
it as a food safe wood finish for drinking glasses) is Varathane
"Diamond" finish, which does not get soft or cloudy after sitting for
several days with a beverage in it.

There are also a lot of waterproofing products at the home centers for
driveways that ought to work. Since you're not drinking the water
dripping off the walls, you probably don't need the UL potable water
listing, and could use one of those products.


Our school has a wood framed straw bale greenhouse with a mud/cement
plaster mixture on the walls. Any creative ways to waterproof or seal
this wall from water damage inside our warm & wet greenhouse?

Cheers!

-Sara

><((((?>`?.?.???`?...?><((((?>?. ???`?.?. , ..
><((((?>`?.??.???`?...?><((((?> 
 
Sara Benjamin 
"Once Upon a Wetland?" Project Director
Oak Grove School 
220 West Lomita Avenue 
Ojai, California 93023 
 
805.895.1241
benjamin_sara at yahoo.com
http://www.oakgroveschool.com/teaching/wetlands.html