Rigid foam retrofit over stucco
I live in Columbus, Ohio and I’m getting ready to start a new project. It’s a 1930 craftsman house that’s been abandoned for about 12 years. We just bought it from the city.
The exterior of the house is stucco over brick (it’s original as far as i can tell), and the interior is plaster right over the brick. The stucco is not in great shape and I want to insulate the exterior anyway (rather than the interior–for a whole host of reasons: space, issues with insulating brick on the interior–plus I’m hoping to keep all that plaster right where it is). So to insulate, I plan to put 4-6 inches of reclaimed polyiso on the exterior, then a ventilated rain screen and (probably) concrete board siding. (Same with the roof, but then a metal roof).
My question is about a WRB. Do I need one? The original final exterior was the stucco, but it’s got a lot of cracks, and I know stucco takes on a lot of water anyway. Plus I really want an air tight house.
If I do put one on, should it go over the stucco or the polyiso? Do I just paint over the stucco with a fluid applied? If I do that, what about polyiso getting wet? And do I need an expensive LAWRB or could I just use drylock or something? I keep going back and forth, and just need to talk it out with some people in the know.
Oh, yea! And what about flashing the windows? (I’m putting all new ones in).
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