Why Plaster Walls Crack and How to Fix Them

Repairing Small Plaster Cracks and Holes

Common fasteners do not perform too well when used on plaster, and the results are often unattractive holes or cracks. Settling or shrinking of walls also causes fine cracks. Luckily, small, narrow cracks can be filled with patching plaster or a better grade of lightweight non-shrinking, ready mixed spackling compound. Avoid joint compound in these cracks. Although it feathers more easily for larger seams, it shrinks more and is not as strong on larger areas.

  • Remove loose plaster and with a screwdriver or knife, cleaning the crack so it is wider at the bottom than on the surface. This allows the new plaster to stick better.
  • With a brush or damp cloth remove all loose plaster dust. If water mixed patching plaster is used, dampen the crack.
  • Fill the crack with ready mix spackling compound or patching plaster, using a criss-cross motion to work it in.
  • With a 6 inch wide flexible putty knife, feather the edges of the patch, about 2" on each side of the crack, so it will be less visible. Using smaller knives tends to gouge walls.
  • When dry, sand lightly and paint. Using a hairdryer on damp days, at a low temperature, will speed drying, if needed. Be careful, too much heat and you'll get fine cracks.