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Heating & Cooling

Crawl Space insulation

I am preparing to encapsulate my crawl space and want to insulate the cinder block walls.  I do not want to have to install a thermal fire barrier.  Is Thermax appropriate for this situation?  Does Thermax absorb moisture?  If Thermax is appropriate, should it be installed directly on the block wall?  Can it be covered by the encapsulating vapor barrier? 

Are there other insulation options for a crawl space where I wont need a thermal fire barrier?

Thank you very much.

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Posted 2017-09-07T18:01:17+0000  by SteveInPA SteveInPA
Hello StevelnPa and welcome to the Community.

Here is an attachment For Thermasheath3- Data-sheet.

I would like to point out a few pertinent facts:

 DO NOT leave Thermasheath-3 exposed. Polyiso foam is an organic material which will burn when exposed to an ignition source of sufficient heat and intensity and may contribute to flames spreading.
 Installations utilizing Thermasheath-3 must be fully protected on the interior side of the building by a thermal barrier such as a minimum of 1/2" gypsum wallboard. Masonry or concrete that is a minimum of one inch thick, plywood that is a minimum of 1/2" thick and wood that is a minimum of one inch nominal thickness may also be recognized as suitable thermal barriers. Consult your local Building Official for specific governing codes and requirements.
The interior and/or exterior of the building should be protected with a suitable vapor retarder and/or a water resistive barrier, if required, based on local Building Codes and climate zone.

Here is some installation information from Owen-Corning insulation about how to insulate a crawl space.

Click on this link for an Installation video for conditioned and un-conditioned crawl spaces.

An important step is to contact your local municipality for the building codes in your area.

Please let me know if I can be of more assistance.


Posted 2017-09-07T19:43:32+0000  by Char_HD_CHI
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