[Greenbuilding] Tear resistant Crawl Space Vapor Barrier

[Chris Green]

Irina Golfman wrote:
> Hello,
>
> We are putting a vapor barrier in the crawl space and I am trying to find 
> something that would be more resilient than the 8 mil poly. I am concerned 
> that the standard 8 mil polyethylene will be compromised the first time I 
> have to go down to change my water filter even if I try to create a "safe" 
> path with boards. 
How about getting some of those lumber tarps made from plastic with 
woven polyethylene fibers inside-- the ones that look like rice bags, or 
the bags used in earthbag construction, and then Tuck Tape them to the 
poly as a reinforcement?
Placing river sand or clayey subsoil material where your path(s) will be 
will reduce the risk of tearing the poly and the lumber tarps.
You can pick these up from lumber yards or from neighbourhood buildings 
contractors for free, since that means one less bit of stuff to figure 
out how to dispose of.
Your only expense, then, will be for the roll(s) of tape.
Two points:
Seal the holes in the lumber tarps with tape.
Tape the edges completely so that the whole assembly is a sealed double 
layer.

If the poly is punctured, you'll still have a tough back-up layer above 
it. You could even use two layers of the tarp material if you wanted to 
do the extra work, or fold the tarps in half or thirds ( the tarps are 
actually quite wide... perhaps 8 feet or so.)

Another method would be to fill polyethelene bags ('sandbags') with 
fairly dry clayey subsoil, as in earthbag construction, and lay down a 
path on top of the poly. If the poly is punctured, the bags can 
reasonably be expected to act as a gravity-powered pressure seal.

Cheers,

Chris Green.