I just discovered that the guy who built the addition on the house we own put a clear plastic wrap on the outside before he attached the siding. Since we also have a vapor barrier on the insulation in the walls and ceiling, I am concerned that moisture may be trapped in the walls.
Is this a reasonable concern or have they changed the rules again?
Re: What would you do about exterior plastic wrap.
You should be real concerned if that is what was done. No rules of physics have changed. The moisture that gets through to the cold plastic will condense and 'rain' on the warm side of the plastic. Not good. The wood inside the plastic will get wet, and decay in very short time. The mold may cause allergy or health problems.
I would suggest a long talk with the 'builder' as to why and get opinions of what to do from experts in the building field. I would doubt there could be any justification for such construction techniques.
Re: What would you do about exterior plastic wrap.
It may not be plastic at all. It might be a product called tyvec. It looks like white plastic but it is a spun product that blocks wind but still breathes.
Re: What would you do about exterior plastic wrap.
One of the top 3 insulation manufacturers offers their product "encapsulated", in other words, sandwiched between 2 sheets of plastic. Your specific climate dictates where the vapor barrier goes. Perhaps they figure they've got all of us covered with a barrier on both sides.
Re: What would you do about exterior plastic wrap.
It depends on what the wrap on the outside was. House wrap (Tyvek, Pink Wrap, etc) is designed to allow moisture through so that any that gets into the wall can get out again. Once the moisture has passed through the wrap, it can run harmlessly down between the wrap and the siding without soaking the wood sheathing. Sometimes a layer of foam is added over the top to keep the moisture from freezing before it gets through the housewrap.
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