Tips on Repairing Cracked Plaster Walls


Cracks that are found in plaster walls or drywall can grow in size thus resulting to the plaster to pull away from the lath behind the plaster. If this happens, you will definitely have to do an extensive repair. Rather than doing major repairs, it is recommended that you repair any cracks once you notice them on your plaster walls or ceiling. You can find some of the tips that can assist you when you want to repair cracked plaster walls.

What you need:

  1. Dust mask
  2. Carbide Tipped Scoring Tool
  3. Shop Type Vacuum
  4. Fiberglass Mesh Tape
  5. Setting Type Joint Compound like Easy Sand 90
  6. Premixed Joint Compound like the Plus 3
  7. 6-inch Taping Knife
  8. 12-inch Taping Knife
  9. A couple of 5-gallon Buckets
  10. Medium Grit Sanding Sponge


  1. When you notice any cracks, you have to open the cracks using carbide tipped scoring tool or a utility knife, but make sure not to cut through the plaster’s wood lath.
  2. Clean up all the dust or debris found near the cracks by using a shop-vacuum until it is free of dust or debris. These loose dusts normally prevent your new plaster from bonding along with the existing plaster.
  3. The next step is to mix some setting type joint compound like to a medium consistency. Once finished mixing it, force the mixture into your crack walls and wood lath using 6-inch taping knife. Ensure that the mixture is not too thick and not too thin.
  4. Before you apply the fiberglass mesh tape onto the affected area on your walls, make sure that you leave the joint compound to set in completely. Try to use yellow or blue colored tape for easy viewing and ensure that when you apply the tape, it is in straight lines. Do not curve the tape because if it is not straight, the tape will buckle.
  5. Then, apply two or three coats of pre-mixed joint compound. Spread them thinly right over your fiberglass tape and you can use water in order to thin the joint compound. The more thinner that you managed to spread, the more smoothly it will apply. Then, leave them for at least 24-hours to allow them to dry thoroughly between coats.
  6. Once the final coat has dried completely, proceed with the sanding process in order to make it smooth using a medium grit sanding sponge. This must be primed using latex primer, which is good in terms of quality namely the drywall primer or PVA primer before you start to paint them.
  7. Always wear a dust mask when you are working with mixed powdered plasters as well as when you are creating plaster dust because plasters contain lime is dangerous to your lung.

Additional Reading:

Black & Decker The Complete Guide to Finishing Walls & Ceilings: Includes Plaster, Skim-coating and Texture Ceiling Finishes (Black & Decker Complete Guide)

The Natural Plaster Book: Earth, Lime, and Gypsum Plasters for Natural Homes (Natural Building Series)