Plaster is a wall covering that has been used throughout the ages. Before drywall, plaster was the primary means for covering most, if not all, of the interior walls of a home or dwelling. Today, plaster has taken a back seat to drywall, however, it is still in use. If plaster has become lumpy or bulging, it may be necessary to smooth it. Smoothing plaster can be done by the average homeowner, and it can be done in as little as an hour.
Make sure that the plaster is sturdy enough to be smoothed or sanded. Sometimes the area behind the plaster will become damaged, and attempting to smooth the plaster will cause greater damage.
Gather the necessary tools for the job. You will need a 1-gallon water bucket, sponge, putty knife, sanding sponge and a small bucket of spackle.
Smooth The Area
Rub the area with a damp sponge. Fill the bucket and use the sponge to gently wipe the area in a circular motion until the large lumps have been smoothed. You only want to smooth any lumps and ridges using the wet sponge, the fine finishing will come later.
Refill any voids using the spackle and putty knife. Once the plaster is completely dry, gently sand the area using a dry sanding sponge. You may dip the sanding sponge into water to get a finer finish.