How to Skim Coat Rough Plaster

Change the texture of a wall with skim coat. This process smooths the surface enough to apply wallpaper evenly, with no ridges or bumps. Although it takes about three days to skim coat a wall, the steps involved are easy to follow.

Instructions

1. Scrape off all loose material and dirt from the wall's surface with a wire brush. Then clean the wall with a damp sponge to remove dust and use soapy water to remove grease.

2. Fill cracks with joint compound after they are cleaned out. Cover the cracks with drywall tape to ensure that they don't reopen later.

3. Apply joint compound evenly to the whole wall with a trowel, starting at the top of the wall and working in one direction. All your strokes must be horizontal for this first layer of skim coat. Allow the joint compound to dry for about 24 hours.

4. Add another layer of joint compound. Start again at the top of the wall, but work straight down this time. Your trowel leaves vertical lines to fill in the ridges left by the first application. Let the compound dry for another 24 hours.

5. Sand the wall with a sanding sponge to get rid of any ridges left by the trowel. You can minimize these ridges by sanding the wall between applications of joint compound. Fill in any gaps in the skim coat and let the wall dry completely before you hang wallpaper.