Plastered Walls

Plastered walls are composed of three layers: a base coat, a thick coat of plaster for strength and a finishing coat for appearance. These may be applied over wood lath, metal mesh, special gypsum wallboard or masonry.

Patching Fine Cracks

• Widen the crack to about 1/8-inch with the tip of a lever-type can opener.
• Blow out the dust and debris.
• With your finger or a putty knife, fill the crack with spackle.
• Sand the spackle when dry, using a block wrapped with fine-grade sandpaper, sanding in a circular motion.
• Prime the patch with sealer before painting.

Patching Wide Cracks

• Undercut the crack with a lever-type can opener or a putty knife to help bond the new plaster.
• Blow out dust and debris.
• Dampen the crack with a wet paintbrush or sponge.
• Use a putty knife to fill just over half the depth of the crack with patching plaster.
• Score the plaster with a nail when firm, but not hard, to provide "bite" for the next layer.
• Wet the dry patch again.
• Use a broad knife to apply the next layer to within 1/8 to 1/4 inch of the surface.
• Let the patch dry before applying the finish coat.
• Fill with finishing plaster and scrape with a straight edge to remove excess plaster.
• Experiment with different ways to achieve a good match for existing textures.
• When dry, prime and paint.