Detailing a Vapor Retarder
I Hope everyone is doing well. I am looking for insight, feedback on the following situation.
context: old Victorian, 2 floors, single family home converted (long time ago) into 2 units condo. No work was done to insulate top and bottom at the time.
Recently did sound proofing work and packed the space between top and bottom units with lots of stuff (see diagram).
No vapor barrier was installed. Now, all materials are off-gassing into top floor unit through old subfloor (lots of gaps between planks). Causing air quality issues (burning nose, throat). VOC Fest for the last year with no sign of subsiding.
Failed Mitigation: 3 coats of AFM SafeCoat, Polyureseal BP on top of subfloor + silicon gel around baseboards. Seal didn’t do well around wood filled area and because of the old floor flexing.
Last resort: Sheet of 6 mil poly vapor barrier on top of old subfloor + taped at edges and overlap + new 5/16 nailed down finished floor on top.
– what US available tape for taping vapor barrier?
– closing up inner space ok from a moisture standpoint?
– What class of vapor barrier in such context?
What are your thoughts?
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