Air-Sealing, Insulating, and Vapor Control for Rim Joist
Sorry to ask about this a few times, I’m just confused about what’s necessary in order to avoid wood rot. I’m trying to insulate the rim joist in my 100 year old house. I don’t want to use spray foam, and I can’t use rigid foam board since the joist bays are irregularly shaped with lots of wires, pipes, other joists, etc running through many of them. I would like to insulate and air seal the rim joist with low VOC products. Currently, I just have some mineral wool batts stuffed in the rim joist bays by a previous contractor. But I would like to add proper air-sealing, as well as a vapor barrier if that’s necessary. I spoke to 475 on the phone yesterday, and they suggest: 1.) air-sealing: apply one to two layers of Visconn to the interior of the rim joist — they say the 1/8 inch thickness of dried Visconn will create a sufficient air barrier, 2.) insulating: place my current mineral wool batts right up against the Visconn once it dries, and 3.) vapor barrier: cover the interior-facing side of the mineral wool batts with Intello Plus. Is this the correct way to air seal and insulate a rim joist from the inside of the house? Do I really need BOTH the Visconn AND the Intello? Could I get away with just one of these mated with the mineral wool batts? Any and all advice would be much appreciated. Thank you.
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