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Discussion Starter · #1 ·
So a HO has decided to put plastic up over the interior of the walls which are already insulated. 2x6 walls, not sure the r-value of the insulation. Exterior is plywood, tyvek, and vinyl siding. He was told to take the plastic back down because it will cause the walls to"sweat". What do y'all think? Don't know the original reason why he put the plastic up. Thanks
 

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It's common to do that here as a vapor barrier.
 

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Sean
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Where - by watching TV & thinking that something is good in northern climates is great elsewhere...

Unfortunately the codes also adopted something similar trying to prevent diffusion in northern climate zones thinking that was what was rotting out walls. Fortunately that is going bye bye - the only location putting plastic in the walls might be considered worthwhile is in houses where there is no AC & you are in a heating climate only

So yes being in Kentucky, it needs to be pulled & no vinyl wallpaper either
 

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What does the energy code there require. In Minnesota, we poly and seal the entire interior of the house. " warm side of the wall".

Ky would be possibly exterior warm side.
 

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Discussion Starter · #7 ·
I am not sure. I will look into it. I'm a framer, not an insulator. I do know that of all the houses I've built (15 years ), ive never seen plastic covering batt insulation. I think I have seen it on some old demo jobs though....
 

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What they said, different climates different rules. Here in canada you MUST install plastic on the inside, it's building code and you're walls will be black and fuzzy in no time if you don't. Infact not just install plastic, but seal it in with accoustic caulk and tuck tape making as close to an air tight seal as humanly possible. Thats the problem with DIY TV, they maybe do it perfectly where they are.. but elsewhere it's a big NO no. Damn you mike holmes! :)
 

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If the insulation is batts with a facing and you want to put a poly over it, my understanding is that the facing needs to be sliced in a few places to prevent moisture from being trapped between the two. At least here in Oklahoma.
 

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Was an insulation contractor for 10 years. As least in the PNW we always poly'd the inside walls... but not ceiling... to drive the moisture given off from breathing and "life" to the attic space where it was ventilated to the outside through "adequate" attic ventilation.
Cannot speak for other parts of the country.

Complete vapor wrap should require an air exchanger to move the moisture from inside the home to the outside.
 
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