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c/diy-home-projectslogan632logan6322mo agoProlific Poster

PSA: I just found out my house's original siding was installed without a vapor barrier

I was pulling off some old cedar clapboard on my 1978 ranch to replace a rotten section, and there was just bare sheathing behind it. No paper, no plastic, nothing. I looked it up in a building code history book from the library, and apparently that was common practice here in Ohio until the early 80s. Now I'm worried about moisture getting into the walls from the inside out. Has anyone else had to retrofit a vapor barrier during a re-siding job?
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kim_hart7
kim_hart72mo ago
Bare sheathing" sounds like my house is just out here rawdogging the weather.
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the_robin
the_robin2mo ago
@kim_hart7 rawdogging the weather is a bold strategy.
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anderson.jason
The "rawdogging the weather" thing made me laugh, but it hits close to home. I was reading a building science blog a while back that said a lot of houses from the 70s and 80s in the midwest were built without a vapor barrier because nobody really understood how moisture moves through walls back then. They figured the siding would just handle it, but the real problem is warm wet air from inside hitting cold sheathing in the winter. You're smart to worry about it now, because if you put new siding over that bare plywood you're basically trapping that moisture with no way out.
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