How to Fix the Cracks on an Oil-Based Wall

Spread a plastic tarp over the floor under the wall crack to protect the floor during the repair process.

Insert a slotted screwdriver into the top of the crack as far as possible. Pull the screwdriver downward along the crack to enlarge it to approximately 1/4 inch wide. Wider cracks hold the joint compound better than thinner cracks.

Measure the length of the crack using a ruler or a tape measure and cut a piece of fiberglass mesh tape to the same length using scissors.

Press the adhesive back of the tape over the center of the wall crack and smooth the entire surface using your fingers to remove any bumps.

Pry the lid off of a bucket of joint compound and scoop up 1/4 cup using a putty knife. Hold the putty knife at the bottom of the tape and spread it upward in a layer thick enough to completely cover the tape.

Wait until the joint compound dries completely and no longer feels damp.

Wrap a piece of fine-grit sandpaper around a sanding block and sand the surface of the wall until the joint compound lowers to the same level as the remaining wall surface. When properly sanded, you can rub your hand over the wall and it feels perfectly smooth.

Wipe the entire wall surface with a tack cloth from top bottom to remove all of the sanding dust.

Open a can of oil-based primer and apply it to the repair site using a paint brush or a roller.

Wait until the primer dries and then open a can of oil-based paint in the same color as the remaining wall. Apply a coat of the paint to the repair with a paint brush or roller until covering the primer. If you don’t have a matching paint color, repaint the entire wall surface instead of just the repair site.