Is it ok with plastic behind wind barrier?

[StraNic]

Mother-in-law has bought a townhouse from the 70s that we are completely renovating. It was inspected and found okay before purchase, but when removing wallpaper, we found a spot with mold, and when we tore up the plasterboard, it was a bit damp behind the insulation (outside). It also turned out that behind the wind barrier (kind of like asfaboard), they had placed plastic, meaning there was plastic both on the inside and outside of the framework. Was this ever standard even in the 70s? The sill seems okay otherwise, but it doesn't feel great to just seal it up again and hope for the best. Note that we suspect the moisture in that area is due to the fact that they had a planting with soil up to the bottom edge of the brick, which we intend to dig away, plus there is a heating coil along the entire sill to counteract moisture. What can/should we do? Attaching picture

 

[Jonatan79]

Not a common or smart construction. Traps moisture as mentioned. Normally, you have a wind barrier on the outside and plastic/vapor barrier on the inside. It might be good to inspect if there are leaks in more places.

 

[postkontrollen]

My mother-in-law has bought a townhouse from the 70s that we are completely renovating. It was inspected okay before purchase but when tearing off wallpaper we found a spot with mold and when we pulled up the plasterboard it was a bit wet behind the insulation (outside). It also turned out that behind the wind barrier (like asfaboard) they had put plastic, i.e., plastic both on the inside and outside of the framework. Could this even have been standard in the 70s? The sill seems okay otherwise but it doesn't feel great to just seal this up again and hope for the best. Note that we suspect the moisture there is due to them having had a planting with soil up to the bottom edge of the brick, which we are going to dig out, and that there is a heating coil along the entire sill to counteract moisture. What can/should we do? Attaching picture

Unfortunately, some houses were built with plastic both on the inside and outside. Perhaps not very common but it did occur. I have seen it myself and it came from the industry and not DIY builds where it incidentally also occurred.