# Crawlspace Vapor Barrier



## Windows on Wash (Aug 30, 2011)

Seal the vapor barrier to the crawlspace wall. It is easier and and you don't want any of the moisture/earth smells moving inside gaps in the foam board if you don't get it sealed up perfectly.


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## cbaur88 (Jan 25, 2011)

Windows on Wash said:


> Seal the vapor barrier to the crawlspace wall. It is easier and and you don't want any of the moisture/earth smells moving inside gaps in the foam board if you don't get it sealed up perfectly.


Thanks WW, what's the best way to attach the foam boards to the foundation wall? I'll try a sealant but the wall is not flush flat, allot of excess mortar sticking out which I guess I can chip away but just in case is there some type of nail,screw, sinker that will hold these babies up against the wall. Thanks a bunch once again! :thumbsup:


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## titanoman (Nov 27, 2011)

Liquid nails or Eagle Grip.

Sent from a Samsung Galaxy S2


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## Gary in WA (Mar 11, 2009)

Additional work may be required if in a termite or radon zone; http://energy.cr.usgs.gov/radon/rnus.html
http://termites101.org/termite-basics/termites-by-region
You may need a p.t. plate holding the plastic to the concrete at exterior grade level with the top open for termite tunnel inspections.....

Gary


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## cbaur88 (Jan 25, 2011)

GBR in WA said:


> Additional work may be required if in a termite or radon zone; http://energy.cr.usgs.gov/radon/rnus.html
> http://termites101.org/termite-basics/termites-by-region
> You may need a p.t. plate holding the plastic to the concrete at exterior grade level with the top open for termite tunnel inspections.....
> 
> Gary


Thanks for the info Gary but that's all greek to me. I think I understand what a P.T. plate is but not sure what you mean by it holding the plastic to the concrete. From what I've read the PT plate should be somewhere on the sill ledge and installed at construction. So far I see no signs of termites down there so that is good news. Perhaps a termite inspection and regular preventative maintenance will keep it that way going forward.


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## Gary in WA (Mar 11, 2009)

You may want the plastic to extend up the wall only 6" or so. The plastic is stopped from completely covering the wall to inspect the wall for termite tunnels. If not a concern, fully cover with insulation. Supply exhaust air if converting to a conditioned crawl...

Treat it as a basement wall, no plastic above-grade to condense water in Summer; http://www.buildingscience.com/documents/information-sheets/crawlspace-insulation/

http://www.buildingscience.com/docu...rawl-space-construction-performance-and-codes


Gary


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