Smooth the surface of dry wall or plaster walls by learning how to skim coat a wall. Skim coating is the process of applying thin coats of joint compound to rough areas of an existing wall to give it an even surface prior to painting.
To skim coat a wall, you need:
- Joint compound
- Wide putty knife
- Compound Pan
- 120 grit Sandpaper
- Drop cloth
- Prepare the wall. Remove nails or picture hangers from the wall. If the wall has a shiny paint surface, sand it lightly to remove the shine or prime the wall to create better adherence of the joint compound. Wash off any greasy fingerprints with detergent. Tape around door, windows, and baseboards to protect them. Cover the floor with a drop cloth. Prepare the joint compound per the instructions on the label.
- Fill the compound pan with joint compound with just the amount you need for the moment. Move the compound to the near edge of the pan so it will be easy to pick up with the putty knife. Load a portion of joint compound onto the putty knife and apply it to the surface of the wall in a 1/8 inch thick coat. Smooth the joint compound completely leaving no thick edges or ridges.
- Skim the joint compound. Once the surface is covered, begin to skim the excess compound off immediately by holding the putty knife at a 30 degree angle and pressing hard in parallel strokes back and forth across the area. Return the excess compound to the pan by scraping the knife on the rim of the pan after each stroke. Scrap off any ridges. Wait 30 minutes before sanding off bumps or rough spots in the compound with sandpaper. Dust the wall with a vacuum or damp cloth.
- Second coat. Apply a thinner second coat using a skimming stroke in the opposite direction of the first coat of compound. Let the coat dry for 30 to 60 minutes before sanding the area smooth. Apply additional coats if necessary.
- Work in a room with proper ventilation and wear protective gear to protect eyes and lungs.
- Let the joint compound dry on the putty knife and compound pan. Use a scraper or putty knife to chip the compound from the pan into a trash receptacle. Never wash compound off tool over a sink or drain to avoid clogging or damaging pipes with dried compound.