I'm working on replacing the carpet in our basement bedroom with some vinyl laminate flooring. I noticed that the concrete appears to have domed cracked / domed in the middle so I need to flatten before I can put the floor I and I thought a layer of self-leveling cement might be the easiest.

I know the drywall is supposed to be a minimum height above the cement to allow for expansion. If I pour a layer of self-leveler it will likely come up to the drywall removing that expansion gap. Is that a problem? A few videos I've watched don't seem too concerned about it.

  • If the concrete is domed, why add filler to the 99% that's lower? Simply grind down the high spots and eliminate the expense of self leveling compound and the concern about it hitting the drywall.
    – FreeMan
    Oct 11, 2023 at 15:44
  • 2
    Having dome concrete might be from a bad levelling job. Dome and cracked might be something else. Measurements(how high the dome) and pictures will help.
    – crip659
    Oct 11, 2023 at 15:53
  • Funny what we "know". Drywall is one of the most thermally stable materials in your home.
    – isherwood
    Oct 11, 2023 at 19:12
  • I was actually referring to the Concrete expanding with the temperature changes, not the drywall. My concern being the drywall cracking if the Concrete is pushing against it when temperatures change
    – Ryan P
    Oct 11, 2023 at 20:02
  • The real primary purpose of that gap between the bottom of the drywall and the floor is to free the guy putting up the drywall from having to tightly fit the drywall between ceiling and floor. Anything else like moisture isolation, expansion gaps, space to tuck away low voltage wires, mouse super highways, or a neat place to hide your baseball card collection is just a bonus. Oct 11, 2023 at 21:03

1 Answer 1


It seems that you are confusing two things: the purpose of the 1" gap at the base of drywall, and the expansion space needed for flooring.

The 1" gap between the floor and drywall is not to allow the drywall to expand, but to protect the drywall from getting wet and soaking up liquids spilled on the floor. It also gives space for the floor to expand.

But regardless, you can easily cut a new 1" gap by using a toe-kick saw, an oscillating tool, reciprocating saw, or just a plain drywall saw.

  • Since baseboard will cover the cut, even a drywall or sharp knife will do.
    – crip659
    Oct 11, 2023 at 15:02
  • Note that 1" is much more than is necessary. As long as it's not touching it's fine, and it's likely fine even if it is touching unless there's regular moisture in the area.
    – isherwood
    Oct 11, 2023 at 19:13

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