Pressure-treated wood is incredibly hardy, but it doesn't last forever. Its surface can become gray and splintery, which in turn accelerates the weathering process. Or the reddish-brown or natural tone of new pressure-treated wood may not suit a homeowner or do-it-yourselfer who wants a more vibrant color. Painting is a great option for brightening up the wood and for helping it to last longer.
Can You Paint Pressure-Treated Wood?
Pressure-treated (PT) wood has a copper azole liquid compound injected into the wood under high pressure. Copper helps to preserve the wood.
Pressure-treated wood can be painted. Before painting, the wood must be dry both on the surface and internally.
By contrast, before applying stain, pressure-treated wood only needs to be dry on the surface—not necessarily inside, too. The distinction is important because some wood coatings, like stain, are breathable. Other coatings such as paint lock in moisture.
Should You Paint Your Pressure-Treated Wood?
New pressure-treated wood is designed to be exposed to the elements; it needs no additional coating for preservation.
Climate, maintenance, project type, and species of wood play into the lifespan of pressure-treated wood. Pressure-treated pine, fir, or hem-fir that is kept relatively dry and maintained with water repellant can last up to 20 to 40 years.
When pressure-treated wood's copper treatment has lost its effectiveness, painting with exterior-grade paint is a good option to help with preservation.
If purchasing new pressure-treated wood, one alternative to painting is to order color-tinted pressure-treated wood. Usually available in wood tones such as redwood, walnut, or cedar, color-tinting gives the wood deep color and protection that last longer than a paint coating.
Before You Begin
Painting over pressure-treated wood with high moisture content can result in the paint peeling, cracking, blistering, or changing colors.
Test the internal dryness of the pressure-treated wood with a moisture meter. For exterior wood, aim for moisture levels of 15 percent or less. If the pressure-treated wood will be inside, it should be around 12 percent or less. For new pressure-treated wood, this could mean allowing several weeks of drying time before painting.
Pinless moisture meters calculate internal moisture content with an electromagnetic sensor. Pin-style meters require tiny holes drilled in the wood. Meters can be rented or they can be purchased for around $75 to $175.
Equipment / Tools
- Paint roller
- Roller cover with 3/8-inch nap
- 5-gallon bucket
- Roller screen
- Putty knife
- Brush with nylon bristles
- Moisture meter
- Exterior primer
- Exterior paint
- Two-part moldable epoxy resin kit (optional)
- Two-part epoxy wood consolidant
- Oxygenated cleaner
Use a nylon-bristle brush and an oxygenated cleaner or deck brightener to remove dirt, mold, and mildew from the surface of the pressure-treated wood. Areas closer to the ground get dirtier due to splashing. Sections of the wood facing away from the sun are more prone to mold and moss growth.
Test Moisture Content
After the wood has completely dried from cleaning, use the moisture meter to test the pressure-treated wood's internal dryness.
To test the external dryness, sprinkle a few drops of water on the surface of the wood. If the water quickly soaks in, the surface of the wood is dry enough to be painted.
Brush Primer on Wood
Pour the primer into the 5-gallon bucket and add the roller screen to the side (inside of bucket). Use the brush to prime narrow, recessed, or high areas that the paint roller will not reach.
Roll Primer on Wood
Switch to using the roller for large and flat sections. Paint by first dipping the roller cover in the primer, then rolling it out on the screen. Move the roller to the pressure-treated wood. Roll in small sections of about 4 feet by 4 feet. Take your time and work slowly.
Brush Paint on Wood
Let the primer dry for 30 to 60 minutes. Clean out the paint bucket and roller screen. Add paint to the bucket and stir thoroughly. As with the primer, use the brush to address areas that the roller will not fully reach.
Box paint for better color consistency. To box paint, add several gallons of the same color paint in a large container, then mix.
Roll Paint on Wood
Use the paint roller with a fresh roller cover to paint the wood. Apply one coat, then allow it to dry. Paint recoat waiting times can be as little as a half-hour for flat paint and up to three hours or even more for a glossy paint. Apply the second coat when dry.
When to Call a Professional
Small-scale painting projects are manageable by most do-it-yourselfers. But large-scale projects, such as painting a deck or fence, may require the assistance of a professional painting company.