How to Seal Drywall

Once the drywall has been installed on the interior skeleton of your home, the seams between the wallboards must be patched with joint compound. Also known as "mud" among homebuilders and contractors, joint compound provides an air- and water-tight seal between the newly installed drywall, making it an integral part of home insulation and weatherproofing. Mud can also be used to repair holes, both small and large, or to add a textured look to a smooth sheet of drywall.

Joint knives (various sizes)
Joint compound
Drywall sandpaper
Sanding block

Instructions

- 1
  Refer to the mixing instructions on the back of your container of joint compound. Most products arrive ready-mixed, but some must be thoroughly mixed with a small amount of water to ensure proper adhesion to the drywall.
- 2
  Apply joint compound up and down the length of the seam. Use a generous amount of compound to ensure that it fully fills the crevice.
- 3
  Drag the blade of your joint knife along the seam to pack in the compound. Scrape the compound smooth by angling the blade against the seam and moving it down the length of the seam.
- 4
  Continue the above steps for each seam requiring sealing. Conserve compound by scraping any unused "mud" back into the container.
- 5
  Let the compound cure for at least 24 hours, or for the time suggested on the container's label.
- 6
  Wrap a sheet of drywall-specific sandpaper around a sanding block and smooth away any imperfections in the dried compound.

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