Insulating Floor Over Crawlspace
We have a house that was built in the 1990’s using engineered joist systems (BCI/TJI) I-beams and recently had some issues with mice getting at some wiring (we won’t go there right now). Original under floor insulation was standard R-19 kraft backed bats held in place with wire insulation supports that are now a mess of sagging fiberglass rat (mouse) runs. We’re planning to redo the insulation under the floor (above a currently vented crawlspace) and are still unclear as to what product(s) to use the give us good insulating value with minimal mouse problems – emphasis on the latter. I saw that Roxul makes a product that will fit better between the I-joists but didn’t see if and how people were suggesting to install an air/vapor barrier between these batts and the bottom of the subfloor. In addition, there was some discussion of putting polyiso panels across the bottom of the floor joists. I don’t know about most other builders or homeowners but I’ve not come across too many crawl space entrances that would allow a 4×8 sheet of rigid insulation to fit through. This house has a 30×36 entrance at best.
BTW — Zone 5B/6B
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