How to Put Up Knockdown Texture
- 1). Wet the existing wallpaper --- if you're taking down wallpaper --- using a bottle filled with hot water to soften the wallpaper adhesive. Scrape the wallpaper off the wall with a wallpaper scraper. Once you've scraped all of the wallpaper off the wall, sand the surface of the wall with a 60-grit sanding block to remove any leftover adhesive and to add texture to the wall for better drywall compound adhesion. If the wall does not have wallpaper on it, simply sand the wall with the sanding block.
- 2). Wipe down the wall with a tack cloth to remove any powdery residue from its surface.
- 3). Mask off any surfaces, such as molding or window frames, that you do not want to get texture onto, using masking tape. In addition, cover the floor and any furniture with drop cloths.
- 4). Put 2 inches of water in a 2-gallon bucket and then fill the bucket with aggregate texture powder. Obtain a consistency of pancake batter. Allow 15 minutes before moving on to allow the powder time to fully absorb the mixture.
- 5). Add a little more water into the mixture and stir it to obtain a pancake mixture again. Pour the mixture into an airless sprayer.
- 6). Spray the wall in a 3-foot by 3-foot grid pattern, achieving a 40-percent coverage ratio. This means that when you make a pass, 40 percent of the pass should have texture on it. Wait 10 to 15 minutes before moving on.
- 7). Slide a rubber squeegee or a knockdown knife with a rubber edge across the surface of the texture to knock down the high points of the texture. Overlap each row by approximately 3 inches to ensure you knock down the high points consistently. Avoid swerving with the knife, as it will be visible after the project is completed. Wipe the buildup of texture off the knife after every pass, using a moist towel, and continue with additional passes until you have knocked the tips over the entire textured surface.
Source...