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Remove fiberglass batts behind finished basement wall?

dustindawind | Posted in Energy Efficiency and Durability on

My fieldstone basement has finished walls with fiberglass batts between the drywall and foundation walls. Should I basically demo these walls and do it right? 


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  1. Expert Member


    Only if there are problems. Accepted best practices are designed to greatly reduce the chances of building assemblies failing - but not all those built with risky ones do. If your walls are well insulated and air-sealed, and don't have moisture issues, it may be fine to leave them well alone.

    1. dustindawind | | #2

      Thanks. The basement is quite leaky and a humidifier runs from April through almost October (MA zone 6, 1900 home). Having an energy assessment done next week… I’ll at least pull what I can so that they can visualize and recommend air sealing + insulation.

      1. Expert Member
        BILL WICHERS | | #3

        Some of the "will it be OK" stuff depends on your weather. In my area here, SE Michigan, it's waaay too humid for batts in basement walls to be a safe assembly. My brother in law in Denver though, his house is fine -- Denver is *very* dry *all* the time. Rigid foam is safe in either area, and basically everywhere else too, but batts are only really safe in the dry areas.

        If you haven't had any issues for years, then you're probably OK. If you see any mold in there though, then your assembly is not working and you should replace it with rigid foam to be safe.


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