I was recently asked for our painting recommendations for pressure treated wood. Our recommendation is short and simple: Don’t.
From experience and some fact finding:
We do not recommend the use of a conventional multi-coat paint system or varnish. The performance is nearly always disappointing, and repainting often has to be preceded by scraping and sanding.
By nature of its make-up, pressure-treated lumber does not need protection from the elements. If you want to keep your pressure-treated lumber looking new for years to come, here are some simple maintenance tips we recommend.
If you are absolutely set on painting or staining your pressure-treated lumber, here are a few suggestions:
1. Let it set.
If you just bought the wood, let it weather for at least 60 days to allow the chemicals to evaporate and work their way out of the wood.
2. Make sure the wood is dry.
A standard water test will let you know when the pressure-treated lumber is ready. Pour a bit of water on the surface of the boards. If the water beads, it's not dry enough. If the water soaks in, it's ready.
3. Apply an outdoor primer/sealer.
It’s not only water that wants to escape from the cells of the pressure-treated lumber, but natural pitch as well. Once the surface heats up in the sun and starts to dry out, any finish you’ve applied may begin to peel.
Be sure to follow the paint or stain manufacturer’s recommendations and remember that horizontal surfaces will get much more punishment than vertical surfaces.
Another common question we often get asked is whether painting your pressure-treated lumber will cause it to rot?
Generally speaking, creating conditions that trap moisture in wood will make decay more likely. we do not recommend paint or other "film formers" because they do not allow wood to breathe, and they can be more challenging to maintain or refresh than penetrating stains