How to Paint Pressure‐Treated Wood

Cleaning the Wood

Wash small amounts of wood with soapy water and a brush. Use a hard-bristled brush to scrub soapy water into the pressure-treated wood. The harder bristles allow for any dirt and grime to be removed. This works best for smaller projects, like a garden box. Before starting, cover any nearby plants with a tarp or plastic, or move them out of the way.

Use a pressure washer for larger projects. Rent a pressure washer that can spray chemicals like deck stripper and wood brightener. To operate the pressure washer, plug it in and hold the nozzle attached to the spraying wand. Start by cleaning the wood with water, then spray desk stripper on the wood to remove any old paint. Once the paint is gone, empty out the pressure washer, fill it with water, and rinse the deck. Then, spray brightener on the wood if you'd like to lighten it. Unlike stripper, brightener doesn’t have to be rinsed off after being sprayed on. Make sure that the washer tip is at least 6 inches (15 cm) away from the wood once you start spraying. When using deck stripper, consider switching the angle of the sprayer to 25 or 30 degrees. In the case of wood brightener, adjust the spray so it spritzed at a 40-45 degree angle. For both products, make sure that the washer is set to 1,000 psi.

Let the wood dry completely. The wood has to fully dry before you can add any primer or paint, or else these products might not set properly. Don’t expect the wood to dry overnight—depending on the exact type, it could take several weeks or months for the wood to completely dry. Pour a few drops of water onto the wood—if the wood absorbs the water, then it’s dry and ready to be primed and painted.

Secure any loose screws or nails before you add paint. Check the pressure-treated wood, using a hammer or electric drill to tighten and secure any loose screws and nails. It’ll be easiest to apply paint or primer on a smooth surface. Additionally, it will be a lot more difficult to make any adjustments afterward.

Applying the Primer and Paint

Purchase latex-based primer and paint suited for pressure-treated wood. Buy primer and paint that are specifically labeled for exterior use on pressure-treated wood. Make sure that both the primer and paint are latex-based, as oil-based products won’t set as well on the wood. Select several 3 to 4 in (7.6 to 10.2 cm) paintbrushes with synthetic bristles to apply the paint and primer. Latex paint looks fresher and brighter on pressure-treated wood than oil-based paint does. If your wood is especially stained, consider getting a primer that is designed to hide stains.

Apply the primer with a synthetic brush. Select a brush and start adding a coat of primer. If you’re working on a vertical project, brush on the primer from top to bottom. For other projects, make sure that you’re using long, consistent paint strokes. Use lighter strokes to help blend any uneven or dripping paint. Try to keep your primer strokes as long and smooth as possible—adding the primer strokes in short bursts creates more obvious brush strokes, which can make your project look unprofessional. Work in sections that are as wide as the brush.

Let the primer dry for 24 hours before adding any paint. Check your can to see how long the primer takes to dry and wait at least the minimum amount of time specified. The primer’s purpose is to serve as a canvas for the wood and provide a smoother painting surface, which can’t be done until the primer is no longer wet to the touch. The primer shouldn’t take longer than a day to dry.

Add the first coat of paint to the wood and let it dry for 4 hours. Apply the paint in the same way that you applied the primer, using long, even strokes that are the same size as your brush. Blend the paint as needed, using the tip of the brush to remove any lumps or bubbles of paint. Let the first coat dry completely before you add a second layer. Make sure that the paint is suited for wooden exteriors. Check your paint can to see how long it takes to dry. Most latex-based paints dry within 4 hours.

Apply another coat of paint and leave it to dry for 4 hours. Add another layer of paint using your brush, using long, even strokes to get a consistent coat of paint on top of the first layer. This provides a more intense color than just one layer of paint. Give this coat of paint at least 4 hours to fully dry.

Brush on a coat of sealant to protect the painted wood. Most sealants are either water-based or oil-based. Check with a hardware or home improvement store associate to see which type would work best with your project. Apply a layer of sealant onto the pressure-treated wood after the paint has fully dried. This helps prevent any chemicals from escaping the wood and leaking into the nearby grass and soil. For this task, a brush made with natural bristles works especially well. Use a razor blade as needed to remove any excess sealant that has congealed into bumps.