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Old 12-31-2012, 03:01 PM   #1
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Rigid Foam Under Rat Slab


Okay, so I've searched the web and searched through this forum and can't find the answer to one question I have.

I will be pouring a rat slab into my crawl space to prevent the persistent buggers from tunneling under my footing. I also plan to make this a conditioned crawl.

Should I pour the rat slab over rigid foam? Would it make a difference? I'm in climate zone 4c (Seattle)?

Thanks!

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Old 12-31-2012, 04:23 PM   #2
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Rigid Foam Under Rat Slab


Why kind of rigid foam?

I can't hurt.

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Old 12-31-2012, 09:38 PM   #3
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Rigid Foam Under Rat Slab


http://www.house-energy.com/Insulati...Insulation.htm

http://www.wrcc.dri.edu/cgi-bin/cliGCStH.pl?watac1

Gary
PS. install 6mill poly under the whole slab first...
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Old 01-01-2013, 11:25 AM   #4
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Rigid Foam Under Rat Slab


Happy New Year and thanks for the great info in the links!

I was planning on using XPS but do you know if I can use R-Matte Plus ISO?

Thanks
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Old 01-02-2013, 08:44 AM   #5
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Rigid Foam Under Rat Slab


Use XPS under the slabs.

ISOs are moisture sensitive.
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Old 01-02-2013, 09:31 PM   #6
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Rigid Foam Under Rat Slab


The foil-facing is good IF there is a space, but not with a slab over it.... Just don't puncture the foil with rocks or pea gravel (in the concrete mix), hmm.....; http://www.inspectapedia.com/Energy/...urate_Slab.htm

Or it can/will absorb 7 times more water in the test as XPS; http://commercial.owenscorning.com/a...35d75090ec.pdf

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Old 01-03-2013, 01:02 PM   #7
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Rigid Foam Under Rat Slab


hmm yeah...my experience with the foil is that if often gets a small puncture if you look at it the wrong way.

Thanks for the add'l info

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