Repairing Cracks Appearing in Walls and Ceilings

Select drywall joint compound for cracks except for those that are very thin and fine. For such cracks, spackling works well. Alternatives include spackling or repair pastes and powders.

Start repair of a ceiling or wall crack by gently sanding the area along the length of the crack. Use fine sandpaper for this task, as it's mainly to provide a scratchy surface for application of joint compound or spackle.

Remove dust particles and debris with a thin paintbrush or toothbrush to clean the surface and interior of the crack. Cleaning inside the crack allows spackle or joint compound to reach deeper into the crack, offering a long-term fix.

Scoop joint compound or spackle onto the edge of a 2-inch putty knife (or wider if you wish). Start at the highest end of the crack and apply even pressure to press spackle or joint compound firmly into the interior of the crack.

Allow the joint compound or spackle to dry, which usually takes about 30 minutes to 24 hours, depending on the type of sealing or compound material you have chosen. Humidity levels, temperature and type of surface may also affect drying time.

Check the spackle or joint compound for dryness. When first applied, joint compound appears dark gray in color, changing to white as it dries. Dab your finger gently on the joint compound to check for dryness.

Gently sand the repair with fine-grit sandpaper in a circular and back-and-forth motion to remove any bump in the surface of the wall or ceiling due to the joint compound or spackling. Pass your free hand over the sanded area to feel for pockets, ridges, bumps or dips in the repair job.

Check the repair within 24 hours to determine whether a second coat is necessary to fill and disguise the repair adequately. View the repair with natural sunlight as well as lamplight to highlight the area and ensure a smooth finish to the repair job.

Paint over the repaired area with primer before painting.