How to Repair Two Coat Veneer Plaster

Spread a dust cloth onto the floor at the base of the damaged wall to protect the floor from drips of plaster and collect falling debris. Place a pair of safety goggles over your eyes and a face mask over your nose and mouth to avoid inhaling plaster dust during the repair process.

Slip the edge of a wall scraper tool beneath the damaged plaster veneer and apply upward pressure on the blade as you slide it beneath the plaster to pry the damaged plaster from the wall. Remove any remaining dust from the drywall beneath with a nylon brush. Spray the wall with a light water mist to wet any plaster residue. Wipe the wall with a piece of cloth to remove the moisture and as much of the plaster as possible, then wait about an hour for the wall to dry.

Cover the stripped section of the wall with a layer of bonding agent brushed on with a paintbrush. The agent will help the patched plaster adhere to the wall surface. Wait for the agent to dry until it's slightly sticky to touch while appearing dry.

Use a 100-mm broad knife to spread the new plaster over the stripped surface. Begin applying the new plaster at the center of the patch, spreading it outwards towards the edge where good plaster remains. Use a filler knife to cut a light crosshatching pattern in the plaster with the knife tip to make a surface to which the finish layer of plaster can adhere.

Switch to a 150-mm broad knife and cover the crosshatched layer of plaster with a new finish layer. As with the first layer, work from the center of the patch to the edges. Smooth the surface of the plaster with the flat of the knife and feather the edges along the original veneer plaster on the wall to blend it in smoothly. Wait overnight for the finish layer to dry.

Smooth the edges of the patch onto the edges of the original veneer plaster with a medium-grit sandpaper attached to a sanding block. Brush off the plaster after sanding with the nylon brush to remove the residue, then collect any debris in the drop cloth for disposal.