How to Patch an Interior Brick Wall With Mortar & Plaster

Peel away the plaster until you have access to the brick. Remove the old grout from in between the bricks with a grout saw. Place the saw against the broken or damaged mortar and use enough pressure that you lift off the old mortar. Remove 3/4-inch of the old mortar from all areas around the brick.

Clean the brick by rubbing a stiff brush briskly over the surface. The brush lifts off debris and knocks aside any brick dust. Spray the wall with a plastic bottled filled with water until the water drips down the brick. Let the brick dry overnight.

Pour the mortar mix into a plastic bucket and add water, as directed by the manufacturer. Let the mixture sit until you see water pooling at the top and mix again. Spray the wall with more water, which prepares the brick.

Dip a tuck-pointing trowel into the mortar and push into the old mortar. Work your way around the brick, adding more mortar until you completely cover the old mortar and seal the brick into the wall. Once the mortar dries, rub the brush across the surface to clean away any crumbs or dust.

Mix the plaster, following the guidelines of the manufacturer. Spray a thin and even coat of water on the brick. Apply a thin coat of plaster to the wall and let dry overnight. Apply more coats of plaster until the repaired area matches the surrounding wall. Once the plaster dries, smooth out any lumps or bumps with fine-grit sandpaper.