I'm adding a 2nd floor bathroom and have a few insulation questions. Part of the new room will be a knee wall at one end with a sloped roof. Current rafters are 2x4s. The unfinished area runs the full length of the house. I will be using part of that space and part of an adjacent room for the new bathroom. There are currently no roof vents or soffit vents in the unfinished space. What is the proper way to insulate this?
Code here says I need R-18 in existing cathedral ceilings.
1) Do I need to tack 2x2s to the existing rafters and run baffles from the knee wall through the 2x4s up to the attic? I'd rather not loose the ceiling height. It's going to be a pretty tight space.
2) Can I just put 3 1/2" fiberglass in between the 2x4s and then tack 1 inch rigid foam over the top of that insulation and 2x4s and skip the baffles and 2x2s? If I go this route I assume I should use un-faced fiberglass and put the vapor barrier on the warm side of the rigid foam, correct?
Thanks,
Barry
Code here says I need R-18 in existing cathedral ceilings.
1) Do I need to tack 2x2s to the existing rafters and run baffles from the knee wall through the 2x4s up to the attic? I'd rather not loose the ceiling height. It's going to be a pretty tight space.
2) Can I just put 3 1/2" fiberglass in between the 2x4s and then tack 1 inch rigid foam over the top of that insulation and 2x4s and skip the baffles and 2x2s? If I go this route I assume I should use un-faced fiberglass and put the vapor barrier on the warm side of the rigid foam, correct?
Thanks,
Barry