How to Prep and Paint Bathroom Walls

Bathroom walls are unique because they live in a cycle of steam, condensation, and temperature swings that would cause a standard paint job to fail in months. The secret to a finish that stays clean and intact isn't just the paint itself, but how rigorously you remove the invisible film of soap scum, body oils, and humidity-borne grime before the brush even touches the wall. Done well, your paint should act as a protective, washable barrier that resists mildew and beads water. This process requires more focus on preparation than on the actual application. If you skip the cleaning or the primer, you are essentially painting over a layer of future failure. Follow these steps, and you will have a wall that handles the daily shower steam with ease.

  1. Remove Everything First. Remove everything from the walls, including towel bars, switch plates, and mirror brackets. If a fixture is caulked into the wall, slice the caulk with a utility knife before pulling it away to prevent tearing the drywall paper.
  2. Strip Away the Invisible Enemy. Scrub the walls with a mixture of water and a heavy-duty degreaser or tri-sodium phosphate (TSP). You must remove all soap scum and hairspray residue, as these act as a non-stick coating that prevents paint from adhering.
  3. Erase Every Imperfection. Fill any nail holes or dings with a moisture-resistant spackling compound. Once dry, sand the spots lightly with 120-grit sandpaper and wipe away all dust with a tack cloth.
  4. Seal the Foundation. Apply a coat of high-quality, mold-inhibiting interior primer to the entire wall surface. This seals the drywall, provides a uniform base, and ensures the topcoat adheres firmly despite humidity.
  5. Frame the Edges Clean. Use a high-quality angled sash brush to paint a two-inch border around the ceiling, baseboards, corners, and fixtures. Work in small sections so the paint stays wet, allowing you to blend the edges with your roller later.
  6. Roll On the Finish. Using a 3/8-inch nap roller, apply your mildew-resistant bathroom paint in a 'W' or 'M' pattern. Keep a 'wet edge' by rolling into the previously painted section to avoid lap marks.