How to Skim Coat a Textured Wall Smooth

If your home was built before 1980, stop and get the texture (and the paint under it) lab-tested before you disturb anything — old wall and ceiling textures can hide asbestos and lead. Once you're clear to work, empty the room or push furniture to the center and cover it, then tape plastic sheeting over the floor and baseboard and drop cloths across the room. Remove outlet and switch cover plates, pull nails and wall anchors, and wipe the walls down so the compound bonds to a clean, dust-free surface.

You're burying the texture, not sanding it away — so just scrape off the loose, flaking, or sharply raised bumps with a 6-inch knife so they don't poke through the skim coat. Fill any real holes or gouges first; our drywall hole patching guide covers that. If the wall is glossy or was oil-painted, scuff it and roll on a bonding primer so the mud will stick; if it's bare, chalky, or previously unpainted, prime it so it doesn't suck the water out of your compound.

Scoop premixed all-purpose compound into a clean 5-gallon bucket and add water a little at a time, blending with a drill and paddle until it's smooth, lump-free, and about the consistency of thick paint or cake batter — loose enough to roll on, thick enough not to run down the wall. Mix only as much as you'll use in 20-30 minutes so it doesn't skin over in the bucket. Thinner mud spreads and self-levels more easily but needs more coats to build up.

Load a 3/4-inch nap roller and roll the thinned compound onto the wall in a section about 4 feet square, working top to bottom — the roller drives mud down into the texture's low spots far faster than spreading it by knife. Don't try to coat the whole wall at once; joint compound starts setting quickly, and you need to flatten each section (next step) while it's still wet. Keep the coat generous but even, with no heavy runs.

Right after rolling, drag a 12-inch taping knife across the wet compound held at a shallow 10-to-15-degree angle with light, even pressure, making overlapping passes and scraping the excess mud off the blade back into your pan. You're pressing compound into the valleys and shaving the high spots flush — thin, not built up, 'not icing a cake.' Feather the edges of each section so it blends into the next with no hard line. It's the same knife-and-mud technique used to tape and mud a drywall seam, just spread across the whole wall.

Let the coat dry completely — usually overnight — until it turns a uniform bright white with no gray damp patches. Lightly scrape or sand off any hard ridges the knife edge left behind, then roll and flatten a second coat exactly like the first, but run your knife passes in the opposite direction (horizontal if the first coat was vertical) to cross-level the surface. Most textured walls disappear under two coats; deep knockdown or splatter texture takes a third.

Once the final coat is bone-dry, sand the wall with 120-to-150-grit screens on a pole sander (or a sanding sponge), using light, overlapping passes — you're smoothing, not grinding. Set a work light low and angled across the wall so raking light makes every remaining ridge and hollow cast a shadow, and keep sanding until the wall reads flat to both your eye and your palm. Vacuum the wall and wipe it with a damp sponge to pull off the fine dust before priming.