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Re: GBlist: Retaining wall waterproofing

Hi Elizabeth

Zypec is 'green' in terms of product definition and current standards
but it would be worth a further look (I was quite surprised when I
started looking closely at floor finishes marketed as environmentally
friendly and looked at background data sheets on the current mediums,
defoaming agents and levelers used). Zypec, I think, is a form of sodium
silicate (trad. called waterglass), and is the most acceptable form of
concrete waterproofing (as an additive) and damproofing (as a surface
coating) that I have found - to date, a lot better than tar.
I mentioned epdm as an option (among which there are 'greener' versions)
because it is (in most forms) a stabler product than a bituminous
product. I have used it as a waterproofing roofing membrane under
concrete and earth decks - as an alternative to bituminous (torch-on)
products. There are low voc latex membranes, there are even pure rubber
membrane products still available. I do not know the full chemical
breakdown of the various epdm's on the market - it is not my first
choice of product primarily because of the bonding agents used and
secondarily because of the polymers used but there are not a lot of

When I was looking at earth roofs and concrete roof decks - I was
initially attracted to using a pure earth system (alternating sod
layers) and for other applications a pure concrete deck, however it was
one of those situations where I could not provide any guarantees of
performance and could not put the client at excessive risk. Ericksons
early flat roofs on Hornby leaked for quite some time (I'm told) and I
think those were on a bituminous base. Poly might be an acceptable
option as it is a non-chlorine product and could be heat sealed - but it
would be a risk. Anyway I think I've conveyed the drift that it is a
balancing act in which the solutions are to some degree always a little
wrong and a little right. I would like to hear of some of the
alternatives that your working with.

John Salmen

Elizabeth White wrote:
> >Another option is using epdm as a complete subterranean wrap (can
> come
> >in very large sheet dimensions or be glue jointed). There are a
> number
> >of greener options for membrane materials.
> How "green" is EPDM? I've used it quite a bit and find it useful, but
> the
> offgassing is offensive and does not diminish with time, so I try to
> use
> alternatives. Am I wrong?
> --
> Elizabeth White, Sustainable Housing Solutions
> 171 Vesuvius Bay Road, Salt Spring Island, BC V8K 1K3
> (250) 537-2616, fax:(250) 537-2681, e-mail: elizwhite@saltspring.com
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