These days, walls are made from drywall or wallboard. These materials have the advantage of being rigid, straight, and easy to paint. Year ago, however, walls were made from plaster. If you're planning to repaint plaster walls, you should know that doing so is a bit harder than painting drywall. Here are some tips for successfully painting those old plaster walls:
1. Patch any holes first.
With drywall, you can sometimes fill tiny holes with just primer before painting. This does not work well with plaster. If a hole is left exposed, it will just crumble; your primer and paint won't stick to it very well. A few days before you prime your walls, look over the walls for any tiny holes. Circle them with a pencil so you can locate them again easily. Then, use a putty knife to smooth joint compound into all of the little holes. Make sure you scrape over the top well to smooth out the joint compound.
Let your joint compound dry for a day, and then sand it down. It's now ready for painting!
2. Apply a primer.
Even if the wall was previously painted, you'll have better results if you use primer before painting your plaster wall. It will stick to the plaster better than paint so you get less chipping in the years that follow. An acrylic primer formulated for indoor use should be fine. Cut in the edges with a paintbrush, and then use a roller on the walls to save time and yield a smoother result.
3. Use a nappier roller.
When it comes time to apply the paint to your walls (which you should do no less than 12 hours after applying the primer), make sure you use a roller with some nap to it. A roller that's too smooth won't get into the texture of the plaster as well. Buy an extra roller. As you are rolling over plaster, the rough surface can sometimes compact the roller; switching to a new one partway through will yield more consistent results.
4. Give walls extra time to dry.
Plaster walls are a bit more porous than those made from drywall, so they can take a bit longer to dry. Don't touch the walls for 12 hours after painting, and don't hang anything on the walls or push furniture against them for 2 to 3 days.
For more information, or to schedule a professional painting session, talk to a house painting company in your area.