Re: [GBlist] low tech green roof?

[John Salmen <terrain@shaw.ca>]

Hi Alan

Yes I have but with membrane which is readily availabe (Firestone EPDM or
some equiv.seems to be 'in stock' at most supply houses in my experience and
quite inexpensive.), however it is difficult to get a roofer to use it for a
small residential job. I've used Platon foundation drainage as a drainage
board, I've also used gravel which is pretty low-tech. I would avoid using
mineral batts for drainage as they could be an additonal source of water
contamination.

One of the problems with 'green roofs' is the general toxicity of materials
needed to waterproof quickly takes the shine out of the green in my
experience and the complexities of waterproofing are anything but low-tech.
Torch-on and the companion products are pretty offensive materials. Same is
true to a marginally lesser degree for most EPDM materials and glues.  I
would prefer to use a polyurethane membrane like Hypalon or keep to that
family of materials.

And since roofs leak it is useful to look at each component of the system as
providing some degree of resistance.

On the natural side I have always wanted to try a roof incorporating the
inverted sod method (traditional icelandic roof). 7 layers of sod
alternating roots up and down. My thought is that a natural membrane is
formed in the breakdown of the grass under anaerobic conditions - similar to
how ponds form.

good luck and keep dry (having just been involved in getting yet another
flat roof to stop leaking)

John Salmen
TERRAIN E.D.S.

----- Original Message -----
From: "Alan Abrams" <awabrams@starpower.net>
To: <greenbuilding@crest.org>
Sent: Thursday, November 22, 2001 7:35 AM
Subject: [GBlist] low tech green roof?


> this is a request for *practical* information on
> detailing a green roof.  Does anyone have first hand
> experience building green roofs with commonly
> available, more or less conventional building
> materials?  I've looked at a few websites on the
> subject; they seem to require sophisticated membranes
> and drainage matts--I think it would be beneficial to
> be able to build with, for example, torch applied
> modified bitumen and ordinary foundation wall drainage
> matts.  Low-tech is good, no?
>
>
> Alan Abrams, AIBD
> 808 Aspen St. NW
> Washington, DC 20012-2510
> USA
> voice and fax 202.726.5894
> <awabrams@starpower.net>
>
>
> ______________________________________________________________________
> This greenbuilding dialogue is sponsored by REPP/CREST, creator of
> Solstice http://www.crest.org, and BuildingGreen, Inc., publisher of
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> ______________________________________________________________________
>


______________________________________________________________________
This greenbuilding dialogue is sponsored by REPP/CREST, creator of
Solstice http://www.crest.org, and BuildingGreen, Inc., publisher of
Environmental Building News and GreenSpec http://www.BuildingGreen.com
______________________________________________________________________