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Need definitive guidance on how to insulate exterior basement wall wit

HU-546436884
last year

I'm remodeling my basement. Here are the details:

  • Concrete block walls. All of the wall is below grade.
  • There was previous dampness penetration in the walls, but those have been remediated.
  • There is existing framing in place that is roughly 8 inches away from the basement walls (there is an air gap). I am reusing this framing
  • The previous finish job just had flimsy paneling nailed to the studs. No insulation.


So I am remodeling the basement. I have already torn out all the old paneling. There was zero insulation in place. I want to add insulation. How should I do it? Again, I am keeping the existing framing so there will be an air gap, and all the guidance I can find on the internet assumes the framing is going right up against the wall.


Options:


1. Wall > Rigid Foam > Air Gap > Stud > Drywall. I am NOT tearing out this framing, so I will not have the framing directly against the rigid foam, there would be an air gap between the foam and the framing. There are also plumbing lines in place that would have to be cut around since they are directly against the wall. There would be no insulation in the studs at all, so the back of the drywall would be in contact with the air in the air gap. This is also the most expensive option


2. Wall > Air Gap > House Wrap > Studs > Unfaced batt insulation > Poly vapor barrier > Drywall. I saw this on YouTube (https://www.youtube.com/watch?v=KGjO1wddX7A). This house wrap is used as a "backer" to keep the batt insulation in place and gives something of a moisture barrier between the concrete wall and the back of the insulation, and the poly vapor barrier between the insulation and the drywall prevents condensation on the insulation. It is the second most expensive.


3. Wall > Air Gap > Stud > Faced batt insulation > Drywall. Using faced batt insulaiton would eliminate the need for any sort of backing material to prevent the insulation from falling back into the air gap since i could staple the facing off on the front of the studs, but there would now be exposed insulation (the non faced side) in the air gap. The paper facing would offer some vapor protection on the warm side between the insulation and drywall but would not be a vapor barrier like poly would. Also since I can't see through paper it would be harder to get a good install. This would be the cheapest option


I am driving myself crazy with the pros and cons here. What should I do? My preference would be option #3 since that has the cheapest materials cost and least labor but I don't want issues down the road. Suggestions?

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