I'm a new homeowner and went to repair an existing hole in the drywall below our sink (round punched hole in the pictures) and discovered that there's a much larger square hole that was covered by a board (see picture). I only have about 2.5" between the cabinet and the wall making getting tools in there very difficult and there's not access holes in the cabinets in this location. I don't have access from behind either.

I want to seal this off to help stop air flow that's coming through here. Any suggestions of how I might be able to seal this off? I don't care how it it'll look as it's hidden by the cabinets.

Picture of hole with rough measurements Picture of my working area under the cabinet

  • 2
    Is the air flow too cold? Because if cold air is coming through that hole, then closing the plumbing in with the cold air might cause the plumbing to freeze. If too warm or smelly or something, that would be different.
    – mdfst13
    Commented Oct 28, 2023 at 21:26
  • It is cool. I believe the airflow originates from our crawlspace, but traverses some of our wall cavities before getting to here (it's an old house). There's other exposed piping in our crawlspace as well. We thankfully don't have too many freezes(I'm in the Pacific Northwest), but I should probably look into insulation that those then
    – tifkin
    Commented Oct 29, 2023 at 0:02

4 Answers 4


I'm a licensed contractor and have a solution for you. Cut a piece of drywall at least 1 inch larger than the hole. I suggest 2 inches. From that piece you score the backside of the drywall just smaller than the actuall hole in the wall. Break off those 1 to 2 inch wide strips you cut from the back but be careful to leave the front paper still attached. What you will have is a piece of drywall with paper overhanging all the way around your piece to install. Apply mud to those flaps and stick the piece in the hole. Use any fit wood or metal to squeegee out excess mud. It might not look real pretty but the hole will be sealed when dried.


There are many ways, but the fastest, cheapest, and easiest is to buy a roll of insulation bubble wrap, cut it a little larger than the hole, and use a can of foam insulation spray as a glue. Five minutes and you are done.


I generally use this method. IT provides a very strong patch.

  • Cut the hole in to a square hole
  • Cut a square out of another (spare) drywall, its sides should be just under the diagonal of the hole to repair.
  • Drill two tiny holes in this piece
  • Loop a piece of wire or twine through the holes
  • Put adhesive around the edges of the piece
  • Insert it in to the hole, turn it square and pull it tight
  • If you have used a piece of wire, you can twist this around a pencil to hold it tight while the adhesive dries
  • Remove the wire
  • Fill it with a suitable compound, in layers, letting each layer dry.
  • Sand and finish

Use panel adhesive or hot-melt glue to attach almost anything to the drywall, from more drywall to thin plywood to cardboard. That hacked up cabinet looks bad enough that aesthetics aren't really a concern, so just seal it up with a simple panel overlay.

If you want to make it look good you need to fix the cabinet, at which point what you repair the drywall with is moot.

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.