How to Paint Basement Walls

Making over a basement wall can require a little more work than a standard interior wall. Not only do you need to pick the perfect paint color, but you may be working with an unfamiliar material, such as masonry brick. Most importantly, before heading to the paint store, you'll need to check that your walls are waterproof. To do so, it's important to know the most common types of water damage. Then, follow our step-by-step guide for repairing and repainting a basement masonry wall.

Before You Begin: Check for Water Damage

To check whether your basement is waterproofed, start by learning the most common types of water damage. Condensation, the mildest form of water problem, doesn't originate on the outside. It forms when the cooler temperatures of water pipes and walls condense the moisture from warm-weather air and leave it on the surface. Increasing the ventilation, insulating the pipes, or installing a dehumidifier will relieve condensation.

To control seepage from groundwater, install new gutters or fix the existing ones, and slope at least 4 feet of the soil away from the foundation so that water runs away and doesn't seep through the walls. Sealing the interior surface of the walls with hydraulic cement and patching the holes can also cure some seepage problems. If neither of these methods work, consult a drainage specialist.

Once you've ensured that your basement is water-tight, it's time to paint. Expect to spend about an hour preparing and painting a 6x8-foot wall, not counting drying time required for repairs. Before you begin, make sure you know how to brush walls, key cracks, and apply liquid waterproofing agents.

What You Need

• Wire brush
• Small sledge and cold chisel
• Trowel
• Hydraulic cement
• Muriatic acid
• Waterproofing agent

Step 1: Remove Debris

Using a wire brush, remove as much loose mortar and paint as you can. Remove efflorescence with muriatic acid, following the manufacturer's instructions. Rinse the wall and let it dry.

Editor's Tip: Efflorescence is a powdery coating of salts in masonry materials brought to the surface by water migrating from the interior of the material. You'll have to remove it before you paint a basement wall. Mix a solution of muriatic acid and water, strictly following the instructions on the label. Wearing old clothes, gloves, and eye protection, scrub the surface with a stiff-bristled brush.

Step 2: Key Cracks

Using a small sledge and cold chisel, key the cracks in the wall—hold the chisel at an angle and undercut the edges of the crack so the bottom of the crack is wider than the opening. Keyed cracks help keep the patching cement in place. Vacuum the crack to remove the dust.

Step 3: Apply Cement

If the area is not already wet, mist it with a spray bottle. Then force a small amount of hydraulic cement into the crack with a trowel and smooth it down. Also apply hydraulic cement where the wall meets the floor.

Editor's Tip: Also plug wide cracks with hydraulic cement or urethane caulk. Press foam backer rod into a wide crack before caulking.

Step 4: Apply Paint

When the hydraulic cement cures, brush on two coats of a high-quality masonry or waterproofing paint.

Step 5: Apply the Final Coat

For the best results, apply the first coat with a nylon or polyester bristle brush, the second coat with a brush or masonry roller. Work the paint thoroughly into the pores of the masonry, then back-roll the area. Roll a second coat over the wall. If you notice seepage after several days, tiny pores or pinholes are still open. Apply an additional coat to these areas.

Be sure to open windows and use an exhaust fan to provide adequate ventilation. Where good cross-ventilation is not possible, a latex product might be less noxious.