Crawlspace vapor barrier product?
user-2575529
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The local home centers don’t have anything much thicker then 6 mil for poly that I could easily pick up and use for a crawlspace vapor barrier. I have a very small area, less than 100 sq ft, and the proper 10-20 mil thick products I see online have way more material then I need. They also cost quite a bit as well!
I was wondering if it would be a problem to use a EDPM rubber roofing material? I can get a 10×20′ roll for $100 and it is 45 mils thick and in stock at the local home center…
Does anyone think that this would be a bad choice for use in my crawlspace as a vapor barrier on the floor?
Thank you
William
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Replies
William,
EPDM is used as an "underground roof" to go around a house for people who have drainage problems in the basement. I can't see that it would be any kind of problem to use it as a crawlspace liner. I reviewed some forums where other people asked if they could do that and it certainly sounds reasonable.
Here is a GBA discussion of the underground roof or inground gutter.
https://www.greenbuildingadvisor.com/green-basics/inground-gutters
JLC discussion on crawlspace liners - one suggestion to use EPDM as the liner
http://forums.jlconline.com/forums/archive/index.php/t-47770.html
Home Energy Pro discussion on crawlspace liners - another suggestion to use the EPDM as a liner
http://homeenergypros.lbl.gov/forum/topics/sealing-vapor-barriers-to-concrete-foundations?xg_source=activity
Insulating crawlspaces on the Oak Ridge National Lab site - they use the EPDM on the outside of the wall, rather than as the crawlspace liner.
http://web.ornl.gov/sci/roofs+walls/insulation/fact%20sheets/crawlspace%20insulation%20technology.pdf
William, Are you providing some protection for the Poly? If so there is no reason to use anything thicker than 6 mil.
Malcolm, if there is no need to ever get into crawlspace and you live in the area not known for radon - sure. But if you have anything that needs to be maintained down there and soil with bunch of rocks (some sharp, as always) - you need felt and then properly reinforced poly.
I am not even getting into radon issues
Apollo, That's why I asked if he was providing protection. Relying on a more robust vapour barrier for mechanical protection is a suckers game. Put down a smooth substrate and cover the VB with a rat slab. 6 mil a perfectly adequate in those circumstances.
Lucy, thank you for all the wonderful links. Very helpful!
Malcom, There will not be any protection for the Poly for the near future that is why I wanted to go with something thicker. There is also already a Radon mitigation system in place. The poly that is in this area is in poor condition and needs to be replaced.
I should add that there is a full basement with a partial crawl accessible from the basement.
Looks like I will be giving the EDPM material a try!
Thanks for the help everyone.