I'm working on framing a wall where a sliding glass door once sat. In retrospect, I believe I should have used 2x6 lumber to frame the wall, rather than 2x4. While one side sits perfectly flush with the existing wall, the other side (shown in the picture) sits about 1.5" back from the existing wall.

Can I screw 2x4s horizontally to the framing to "shim" the drywall into the correct position?

Also, these are several different things hanging on the existing wall (some sort of cement shingle, tar paper, foam board, etc) Do I need to remove all of these prior to hanging drywall, or should I leave them as extra insulation?

enter image description here

Here is an up close view so you can see the gap between the framing and the existing "wall":

enter image description here

Any advice is appreciated.

  • Your image link for the close-up is broken. Are you making up the thickness of the sheathing, siding and insulation or is the original wall framed in 2x6s? Also, it's not clear why you're drywalling what looks like an exterior wall - is this a newly finished (formerly exterior) space?
    – Comintern
    Jan 21, 2016 at 23:38
  • Fixed privacy rights on the link to close-up. Should be viewable now. And I believe the original wall is 2x4, but it was originally exterior and has some sort of wood sheathing, tar paper, foam board and some kind of shingle. The wood sheathing and other things are what give it the extra 1.5" gap.
    – Adam Hall
    Jan 22, 2016 at 0:27

1 Answer 1


My thoughts the same about drywall @Comintern, to make up the 1.5 it would be easiest to attach 2x4's sideways. If this is now a inside room I would remove the old exterior siding, However the “cement shingles” look like the asbestos type commonly used you might want to have them tested prior to working with them for health reasons. I don’t think I would ever put drywall over the lap siding even with the sheet insulation if now an interior room. If this is still exposed to the elements you really should use exterior sheeting.

  • It was originally an exterior wall and the sliding glass door I removed opened up onto a porch. The porch was converted to a sunroom before I purchased the house, thus the wall is now an interior wall. I'm in the process of removing the siding and putting up drywall, but wasn't sure about the shingles, etc. I had planned to remove them as well, but wanted to make sure they weren't beneficial insulation as the sunroom is very well insulated.
    – Adam Hall
    Jan 22, 2016 at 0:24
  • Also, I think you're correct about asbestos shingles. Yikes. Had no clue. Thanks for the heads up.
    – Adam Hall
    Jan 22, 2016 at 0:37
  • Yep, from the close-ups it appears that the majority of the gap is from the old sheathing, siding, etc. I'd take it down to the sheathing and then sheath the newly framed section out to the original wall plane.
    – Comintern
    Jan 22, 2016 at 2:02

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