The finish coat is applied after the brown coat has hardened.The brown coat is applied over wood lath, strips that are nailed to the studs and spaced about ¼-inch apart to create keyways for the brown coat to grip. Old plaster walls and ceilings are made from two layers of plaster.

Again, be sure that there aren’t any high spots or ridges left behind. Once dry, apply a second coat of the flexible patching compound in the same manner as the first coat.Ensure that there aren’t any high spots or mounds left behind before allowing the compound to dry for at least two hours. Drag the blade of the putty knife across the crack at an angle (again, not perpendicular). It’s important to remove the excess patching compound as it’s not sandable.Start at the top and work your way down, pushing the compound into the crack. Apply the flexible patching compound to the crack.Ensure that the crack is free of debris by scraping the putty knife over the crack.You can handle some small cracks with a two-coat process using a flexible patching compound, and there isn’t any sanding required. If the repair or crack is still visible, apply a third coat and feather the edges with sandpaper once dry.Lightly sand the repair area to remove any high spots and ridges while also feathering the edges of the repair.Wait 45 minutes to an hour so it can dry. Starting at the top of the tape, apply the compound and remove the excess.

Immediately apply a second coat of compound over the top of the mesh tape.

Starting at the top, lightly press the mesh tape into the bed of compound before using the putty knife to cut it at the bottom.

Apply mesh tape over the fresh compound.

Remove the excess compound by pulling the blade of the knife across the crack at an angle (not perpendicular to the crack). Start at the top of the crack and drag the compound down, pushing it into the crack as you go.

Using the putty knife, apply a thin coat of joint compound to the crack.

Look for compound, paint flakes, and other debris in the crack and scrape it out.

Start the project by cleaning up the crack with the utility knife.

After explaining to Kevin that his paint job is only as good as the prep work, the two discuss where cracks are most likely to occur before diving into a few repairs. Mauro Henrique gives Kevin O’Connor a lesson on patching cracks in plaster and drywall.

Plaster wall repair