Painting Over Cracked Plaster
Don't give up and replace it with drywall quite yet — fixing damaged plaster is worth the effort
I removed old wallpaper and ended up with cracked horsehair plaster that feels gritty or sandy. I would like to paint the walls rather than re-wallpaper. Is there something I can do to make these walls look good when painted?
— Deborah, Haverhill, Massachusetts
Steve Thomas replies: While it might be tempting to rip down an old plaster-over-lath wall and replace it with drywall, often the plaster can be saved. Firm plaster that has popped off the lath should be
reattached with plaster washers and drywall screws. After removing areas
that are crumbling, patch holes with two coats of lime putty sandwiched around a reinforcing layer of fiberglass mesh tape. Trowel on the patch in two layers: a fill coat and a thin final coat that blends in with the surface of the wall.
Shallow patches can be primed with a latex primer after a few hours, but allow the wall to dry overnight if the patch is deep or you're using an alkyd primer. Repeat on all damaged areas before reaching for your paintbrush.
For more on wall prep and painting right,
see our article Scrape, Sand, Prime (Repeat).