Seeking advice on siding and moisture…
I recently noted moisture on the interior of my plywood sheathing in cold winter weather (doing a wiring repair that had me access the interior wall). This is probably not surprising. I am in cold zone 6 and have standard wall structure of about 35 years ago; -sheetrock, 3.5″ fiberglass with either kraft or foil facing stapled on to studs, plywood sheathing, a building paper/wrap (Tyvek, I think), and then cedar shingles at 5″ exposure, stained. It did not appear the sheathing was much along toward rotting though, fortunately, but that was just one area.
I’m now thinking of residing, in part due to moisture issue but also due to maintenance of keeping shingles stained at my age now and with a two story house. But now I’m stumped as to what would work and be an upgrade. I’d like to use rigid foam outside the sheathing (for moisture control and more R), but per Martin, none is better than not enough in a case like this. And “enough” is R-7.5, which translates to 1.5″ of xps, or more, since xps loses R value over time (eps might be better here but more depth is needed for R value). I was considering vinyl for it’s low maintenance. Installers usually use half inch of rigid foam below the vinyl, which in my case would seem to be a negative (not enough). If I were to consider more foam, what in the world does one do about the added depth for windows and doors? Some of my windows could be fairly replaced, but some are good vinyl windows only a few years old. No way I would want to discard those.
Has anyone had a similar experience or useful advice?
Thanks so much.
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