Does the facing of polyiso insulation matter when mechanically attaching to a block wall?
The 2009 IRC allows for unvented crawl spaces. To acheive the R-10 for my zone (Maryland) I plan on using recycled 2″ polyiso roof insulation attached with Tapcon screws to the CMU walls. 85% of the CMU is below grade. The facing of the roof insulation I intended to use has a heavy tar paper facing both sides. Does this facing preclude using this roof insulation in this application?
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