Pressure treated wood is fantastic for outdoor use. As the name suggests, it’s been treated with chemicals and sealants that protect it from outdoor elements such as rain, wind, bugs, snow, and mildew. However, if you're not into the natural look and want to paint the wood, you're going to have some extra work to do. While it doesn’t require a lot of additional work, it does require waiting a large amount of time for the wood to be clean and dry enough to paint. Pressure treated wood is completely paintable, but it must be done properly, otherwise the paint won’t last very long.
Step 1 - Clean the Wood
Cleaning treated wood may seem like an unnecessary step in the painting process, but the wood may have collected dust, dirt, and debris during its travels from the manufacturer to your home. Use soapy water and a stiff brush to scrub it clean—in the direction of the grain—not against it. Then rinse it clean with water.
Step 2 - Wait for the Wood to Dry
Regular, unsealed wood usually dries within a few days, but pressure treated wood takes much longer to dry—either weeks or months, depending on what the wood is treated with. Painting the wood before it's dry will be a waste of time because the paint will peel away as the moisture pushes up underneath. Test the wood to see if it’s dry by dripping a few drops of water onto it. If the water soaks in, the wood is dry and porous enough to paint. If the water rests on the surface in beaded drops, the wood must be left to dry longer before painting.
Step 3 - Pretreat the Wood with Primer
You need to use primer first before painting, especially because pressure treated wood is so picky about holding onto paint. Make sure to purchase a primer designed for outdoor use (the exterior kind) with a label suggesting use for pressure treated wood. Without these special designations, your primer and paint job may not last long due to the wood’s resistance to liquids. Coat the wood in the primer according to the label’s instructions. Remember that when applying primer or paint, thin coats dry more quickly and turn out much more evenly than thick coats.
Step 4 - Let the Primer Dry
After applying primer, you’ll have to give it some time to dry. Fortunately, this won’t take more than a day or two, depending on the primer. Check the primer’s label for how quickly it may dry, but remember that you’re dealing with a special, treated wood that will probably need a little extra drying time for best results.
Step 5 - Paint It
Finally, you can paint your pressure treated wood! Apply at least two coats of paint for an even finish. Latex paint works best on pressure treated wood since oil-based paints can resist the surface. A proper paint job should last a few years without too much damage.