Encapsulating a Crawlspace Using Poly and Rigid Foam
Hello GBA community. I am a homeowner acting as a GC. I am ready to encapsulate my crawl space and make it a conditioned space in Zone 5A. I’ve researched here and several other places on how to insulate the interior (CMU) crawl space walls. Some call for Poly sheeting on the wall and then polyiso rigid foam board. Others called for just rigid foam board attached directly to the wall.
What might be the reasoning to add both ? Advantages and disadvantages ?
It seems to me that the easiest and cost effective way to go is to directly attach the rigid foam (2″ Atlas energy shield) to the wall using an adhesive and foregoing the poly sheeting between the rigid foam and wall.
Also – I plan to add 2″ of rockwool comfortboard to the exterior down to the footing. Will these two types of insulation on either side be compatible for the crawl space wall / rim joist?
Michael R. Smith
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