How to Smooth a Textured Wall. While creating a textured wall is great if you want to hide dents, cracks and other flaws, texture is not for everyone. Some people prefer a smooth wall over a textured surface. If you have a textured wall and want to smooth it, it's possible. Smoothing a textured wall is a time-consuming process, but if done correctly, you'll be happy with the results.
Sand off all high spots on the wall if the texture is deep. Wipe off all dust residue with a damp, rough cloth when finished.
Apply a primer to the wall unless you painted with a flat paint. The joint compound you are using to smooth the wall needs a good finish to adhere to. Flat paint or a primed surface is best.
Purchase joint compound from any hardware store or home improvement center. This can come in large 5- to 10-gallon buckets. Measure the wall you are smoothing, and then buy the amount of compound you need.
Spread the joint compound across the wall using a wide putty knife. Apply a few coats, as necessary. Don't sand between coats, but knock off any high spots with a dry putty knife after the compound dries.
Smooth the wall with sandpaper after the final application of joint compound. Fill in any spots, if necessary, and sand those when dried. Wipe wall with a damp sponge when finished.