Fixing Ceiling Cracks & Humidity

Humidity can wreak havoc on plaster or drywall ceilings. It causes the surface plaster to peel, crumble and crack. Before you repair the damage, you need to determine the cause of the humidity, or the damage may return. Moisture damage can be caused by a roof leak, a plumbing leak or other issues. Determining and repairing the cause may require a professional contractor. Once you are sure you have addressed the humidity issue, then it's just a matter of replacing and reworking the surface with new plaster.

Ladder
Drywall knife
Joint compound (plaster)
Paper drywall tape
Drywall sander

Instructions

- 1
  Use your drywall knife to scrape away any rippling or loose parts of the plaster ceiling caused by humidity. Dig out any loose material from the cracks in the ceiling so you're left with only solid surfaces.
- 2
  Spread joint compound into the cracks, just coating the exposed areas. For any crack that's an inch or more in width, rip off a piece of paper drywall tape to that size and press it into the crack, embedding it in the plaster. Spread more plaster over it, bringing it out level with the surface of the ceiling. Repeat for each crack.
- 3
  Let the plaster dry for 8 hours.
- 4
  Spread plaster thinly over all the humidity-damaged areas, scraping it across the surface with the drywall knife. "Skim-coat" the entire damaged area.
- 5
  Let the plaster dry for 12 hours. Sand it smooth with your drywall sander. It's now ready for repainting.

How to Sand a Durock Ceiling

How to Retexture a Ceiling

Ceilings