In our basement we have two different framing setups that support our joists. Please see photos to help explain, but 2 of the walls have plate on the concrete foundation and 2 have for lack of a better term a small wall then the plate with joists on it. Any clue why this was done other that to save money? Also the small wall is insulated with fiberglass batting and covered with plastic. This seems to be leading to moisture and potentially mold issues. Any ideas what the plastic is there for? What is the best way to insulate this space, rigid foam board, spray insulation? enter image description here

  • Is the plastic shown in this picture? I can't see it, is it a transparent layer stapled to the short-wall studs/cripples? Aug 16, 2016 at 1:51
  • many times a this short wall is used because stem walls do cost more and depending on the height and load they require an engineering stamp where a cripple does not. plastic is not so good a breathable membrane would be better in my opinion.
    – Ed Beal
    Aug 16, 2016 at 16:02

1 Answer 1


I'm no expert but sharing what I am doing. Using rigid foam r13 along studs exterior wall which is concrete. I used drylok extreme paint to water proof the porous concrete in my basement. It typically brings moisture in slowly but this should deter it. The 2" foam will act as my moisture and vapor barrier as well. The basement is typically controlled and should maintain fair temperatures. I am using drywall right on top with a 1.5" space between foam and drywall for breathing.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.