I have read information on this topic but its confusing to me. In my case, this is a brand new build and foundation cement was poured last October and is now May. There is black water-proofing membrane on exterior of basement cement wall. On inside of wall there is the TLP R20 insulation wrap from floor level to ceiling level... everything is taped up and air tight. I assume the insulation wrap meets Ontario building code for an unfinished basement.
My question is whether I remove this insulation wrap or not. From what I can tell, the insulation is actually touching the cement which I thought is a big NO NO! If the insulation is actually touching the cement, wouldn't the insulation absorb any moisture coming out of the cement? ... and thus rendering the insulation as useless?
Most responses that I have read suggest to keep the insulation wrap which is my preference as well but I am afraid that moisture will build up using this approach and I don't want to build my stud wall and drywall only to have the moisture problem later...
So......... is there a reason that this insulation wrap works and moisture does not get soaked up by the insulation? ...Your responses would be very helpful!
You need to check with your local building debt. in my neck of the woods the town wants the wrap removed as it sits directly against the concrete and builds up moisture causing mold. The wrap is indeed put there for code but doesn't meet code once you start to finish. We generally use some type of membrane ie Tyvek from floor to ceiling then leave a 3/4" gap to allow air to move then 2x6 studs R20, 6 mil vapour barrier then drywall. the other alternative is a 2"SM then 2x4 studs with R14
Hope that helps
Agree with Mark. If you are going to leave your basement unfinished, leave it up, because while it looks "air tight" it isn't and can breathe therefore mould isn't a problem.
If however, you are finishing your basement, then you'll have to take it down. Put Tyvek (or housewrap - it's waterproof, but breathable) up and the build your walls no less that 5" (to the outside of the wall (inside surface of the room) away from the concrete. Also keep in mind at no time may wood contact concrete so you'll need vapour barrier (strips of 12" poly between wood/concrete).
If you want to insulate the basement from there, you insulate, vapour barrier, then drywall. Don't vapour barrier the outside of the wall as well, this promotes condensation and will cause mould.
Hope that helps.
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