Can you paint pressure treated wood and how to do it right? 

So, you are wondering how can you paint pressure treated wood? Firstly, let me assure you that you can paint treated wood. Moreover, the process is very similar to painting any other kind of treated or untreated lumber. It just takes a bit more patience.

In the following text, I will explain what exactly pressure-treated wood is and how you can paint it the right way. In addition, we’ll take a look at some nuances of surface preparation and paint selection.

Pro-tip: Always pay attention to the edge stickers of your wood, as they contain a lot of useful information on the type of treated lumber and its designated field of application.

What is pressure-treated lumber?

Pressure-treated lumber is your usual wood, but infused with a bunch of chemicals that prevent rotting and parasite infestations. To a certain degree.

The chemicals used during the process usually contain dissolved copper (or particulate) and a mixture of fungicides with insecticides.

Types of pressure-treated lumber

There are several types of chemicals, including water-based and oil-based. The first type is being used predominantly in residential construction (decks, playgrounds, etc.) whereas the second one is exclusively for industrial applications.

A bit on technology

Big high-pressure chambers are used to force the chemical compounds into the wood. That’s the basic principle behind the pressure-treating process. The penetration depths and thus the drying time depends on the cellular structure of the wood, the type of compound, and storage ambient conditions.

Paint behavior on different types of treated wood

When it comes to painting pressure-treated wood, just make sure it is dry enough. Treated wood requires patience.

If the wood is too damp, the paint just won’t adhere to the surface. It is fair for wood treated with oil-based and water-based chemicals. The latter type in addition repels and makes paint thinner due to solvents and oils.

But even if your treated wood is dry enough, its pores are partially occupied by the chemical, which can cause some troubles. Thorough surface preparation will negate such effects. I’ll cover it later.

Pro-tip: Wait for your treated lumber to dry completely before even trying to paint it. It can take up to four months in different storage conditions. Or opt for a kiln-dried treated wood, which will save a lot of time, but will cost more.

Kiln-dried pressure wood aka KDAT

Kiln-dried wood (often marked as KDAT – Kiln Dried After Treatment) arrives at the lumberyard dried to about 19% of moisture content. It is ready to be used in the project right away. Naturally, it has some downsides:

1. Drying in a kiln adds to the cost of such wood.
2. You won’t be able to buy it at your local Lowe’s or Home Depot.
3. It usually takes a couple of weeks to ship KDAT wood to a certain location.

So, if your schedule is tight, then go for it. But I would recommend making a backup stock of regular pressure-treated wood that will sit in your workshop or dedicated storage space.

That way you can take dry wood out of your stock when needed and refill it afterward and always have a steady supply of good dry wood.

What kind of paint will do for pressure-treated wood?

I would recommend using water-based paints unless you are dealing with industrial-grade pressure-treated wood.

As a rule of thumb, you would want to use water-based paint for wood treated with water-based chemicals and, respectively, oil-based paints for wood treated with oil-based chemicals.

NB: The necessity of painting treated wood is negotiable, as treated lumber is already resistant to factors. But it is still vulnerable to corrosion. Aside from its protective function, paint has a decorative value. And I won’t doubt your decision to paint pressure-treated wood because you certainly have reasons to do so.

So the best option is some water-based exterior latex paint in conjuncture with receptive primer. It is true for oil-based paints too. But you can also go for paint and primer all-in-one products.

Just try not to apply any paint without priming and preparing the surface. If your time and budget is allowing, try some pressure-treated wood-ready paints.

Surface preparation

First and foremost, make sure your wood is dry. You have three options to do so:

1. Touch test. Just go to your treated wood and touch it. If it is still wet, you have another month or so to do something else. Alternatively, you can use a paper towel and press it hard against the surface of your boards.
2. Grab a spray bottle with water and spray some over the wood. Dry wood will absorb it. If there are some water beads forming, then it’s not ready yet.
3. Go ahead and buy yourself a digital moisture meter. It won’t cost much, but is very handy when you work with wood a lot. And it shows the temperature too.

The moisture content of your wood should be lower than 19% to even think about painting pressure treated wood.

Pro-tip: Always check your stock in several places. Wood has a lot of variations in density and other parameters even within relatively small portions of volume, so make sure your stock is dry through and through.

It is better to check how dry the wood is even before building stuff. On the other hand, some contractors can build long-lasting, neat, and tidy structures even out of wet wood.

Washing before painting treated wood

Once you made sure the wood is dry enough, it is time to move to clean and sanding it. Make sure there’s no dirt and loose debris on the surface.

Take away dirt by power-washing if needed. In older structures, it may expose decaying pieces that you would want to replace.

Pro-tip: Give the wood enough time to dry after washing. I know long waiting times are daunting, but in the long run, waiting is always better than repainting the whole piece.

On the matter of sanding

The surface of the pressure-treated use is usually rough enough for the paint to adhere. In fact, in regions with moist and warm climates, it has incisions on its surface that help promote the soaking of the chemicals.

If you want to make an extra step and lightly sand the surface, it won’t hurt either. Just be sure to wipe away all the dust before priming.

Primer

After prepping your deck or porch, go ahead and apply a coat of primer. It is better to use the primer that is meant for exterior use or designed specifically to go on the pressure-treated wood.

Priming is the crucial step in ensuring decent adherence to your paint. But you will have to wait until it dries. Refer to the instructions on the packaging to know how long it will take.

Can you paint pressure treated wood? The actual painting of pressure-treated wood

Now, with your surface clean, dry, and primed, you are all set for the actual process of painting pressure-treated wood. Use the paint to apply at least two coats to have a nice and even layer. It is better to wait between coats to make sure everything is good.

The process itself is the same as any other painting job, given that the weather and the type of paint you use are suitable. Refer to the recommendations of the paint manufacturer and trust your best judgment.

And just like that, you had proven that you and anyone else who has the need or desire can paint pressure-treated wood.

Q&A bit

Now let’s dedicate some time to some of the questions that usually appear along with “Can you paint pressure-treated wood?”

How long should you wait before you paint pressure-treated wood?

You will have to wait the exact amount of time your wood will take to completely dry. It can be between one and four months, depending on initial humidity and storage conditions.

Even if the wood is kiln-dried, it is better to let it sit for a week before trying to paint. Check its moisture content from time to time and wait until it reaches 19% or less and then you are good to go.

Is it good to paint pressure-treated wood?

Only if it’s dry enough. When it comes to pressure-treated wood, paint is rather a decorative feature than actual protection. In fact, you can stain pressure-treated wood too.

But, hey, looks matter too. In addition, a nice coat of paint will somewhat protect the wood from sun, rain, and other elements that are the wood’s natural vulnerability.

What happens if you paint pressure-treated wood too soon?

A lot of bad stuff. If you try to paint your pressure-treated wood before it’s completely dry, the paint just won’t stick to it. And it’s even worse if it does. Let’s take a look at some consequences of lacking patience:

1. The paint won’t adhere to the surface of treated lumber and dry at the same time, forming ugly folds, wrinkles, and waves that will chip off eventually.
2. The remnants of the chemicals that are still escaping will become trapped under the layer of paint and form bubbles and chipping areas on the surface.
3. The treated lumber will go over the place as it shrinks while drying. They shrink in length and width, twist, cup, and do a lot of other crazy stuff. Sure, dry water-based latex paints do have some elasticity, but it is not near enough to cope with such kind of shape-shifting.

So just don’t paint your pressure-treated wood too soon. It is better to wait in terms of effort, money, and, quite frankly, time.

And a conclusion

Now you know that you actually can paint pressure-treated wood. Moreover, you have the basic knowledge to do so (given you had read the whole article). It is time to act now.

Go ahead, and put your hands on some primer and paint, and anything else you might need along the way. Or ask a professional painting company to do the job for you.

And don’t forget to enjoy the process of painting treated wood because everything you do will become a priceless experience.