I am drywalling my unheated, partially-below grade exterior garage. A four-foot tall concrete wall runs along the parts of the garage that are below-grade.

Above the concrete walls are 2x6 wood framed walls. The wood is anchored to the concrete and separated with a sill gasket. There is a 1/2 inch ledge so the drywall will be flush with the concrete.

What can I do to transition between the drywall and the cement? I don't want a gap, and I suspect the drywall shouldn't be in direct contact with the concrete.

Before and after: Left: concrete and wood framing, right: concrete and drywall

  • 1
    What is the level of the exterior surface/grade? Is the 2 x 6 sill plate below grade? What is the current situation with the outside wall, how is the exterior surface treated? can you be reasonably confident that there will be no moisture penetration from the exterior, at the sill plate? Apr 26, 2016 at 1:45
  • What qualifies as a "gap"? Any seam at all?
    – isherwood
    Apr 26, 2016 at 13:16
  • The concrete comes 18" above the grade. I just finished backfilling outside the walls after applying a waterproof membrane.
    – shufler
    Apr 26, 2016 at 16:52
  • A seam is fine. This is a garage and I'd rather dust and stuff don't get in the crack between the drywall and concrete
    – shufler
    Apr 26, 2016 at 16:53
  • Also, the outside wall on the other side of the wood framing is OSB with siding that ends below the sill plate
    – shufler
    Apr 26, 2016 at 17:00

2 Answers 2


In my last house a daylight basement the original sheetrock was glued to the cement walls with liquid nails that worked very well. I did pull it all out and add furring for electrical spaces. (I don't like exposed conduit and surface boxes in a room that became my man land). If you are worried about cracking at the sill add a accent trim over the gap.

  • Accent trim -- so like moulding or something similar to a chair rail?
    – shufler
    Apr 26, 2016 at 16:57
  • Yes it would look good and keep it sealed.
    – Ed Beal
    Apr 26, 2016 at 17:17

One possible solution (there are no doubt others, and I'll be interested to see what they are) is to set a strip (4 to 12" wide) of 1/2" cement-based tile-backer board at the bottom edge of the drywall.

  • That's an interesting idea. While I could mud the joint between the drywall and backer board, I think I would still have a gap between the backer board and concrete.
    – shufler
    Apr 26, 2016 at 16:59
  • Caulk or mortar could fill that gap.
    – Ecnerwal
    Apr 26, 2016 at 19:34

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