There are a number of reasons why you might want to paint pressure treated wood. The desire to achieve a certain color or appearance is probably the most important one. Although it is generally not recommended that you paint such timber, there are is a way how to do it. However, it needs to dry for a few months before you can paint it.
In this article, we are going to share with you the exact steps on how to paint treated wood and answer the most frequent questions.
What Is Pressure Treated Wood?
Pressure-treated wood refers to the computer-guided chemical treatment of wood which is performed to give it additional protection from insects and elements of nature. The treatment takes place inside a specially-built vacuum cylinder where necessary chemicals and preservatives are infused into the wood (source).
As part of the treatment, timber pieces are placed inside the vacuum cylinder and the inside air is taken out totally. The timbers are completely dry now. This is followed by supplying the solution of preservatives into the cylinder at high pressure. The timber pieces are completely submerged in the solution and they absorb the preservatives at a very deep level.
After the pressure treatment is over, the timber pieces are taken out of the cylinder and left to dry. Once the timber pieces are completely dry, they are sent for manufacturing different products out of it. Alternatively, they are painted and sold on the market as pressure-treated wood for woodworking.
Can You Actually Paint Pressure Treated Wood?
Professional woodworkers suggest that you should not paint pressure treated wood. This is because the performance of conventional paint on pressure-treated wood is not so great. Even repainting is not as easy as it requires a lot of sanding and scraping.
However, you can run a coat of paint on such wood or stain it if you do not like its brown or greenish shade that comes due to the pressure treatment. Painting this kind of timber is a little different and you will need the right kind of paint to make this venture successful.
Also, you will need to make some extra preparations compared to what you do for painting any ordinary wood. We talk about it later in this article. But the one important thing that we can tell you right away is that pressure treated timber needs to be properly dried for a minimum of 60 days or so before painting them.
Painting Pressured Treated Wood in 4 Steps
To paint the pressure treated timber, the following step-by-step method should be used. The process requires a few months for the wood to fully dry (min. 2 months). You will then need paint, primer and an applicant (e.g. brush).
1. Dry the Timber
The first step towards painting the pressure treated timber should be to dry it thoroughly. It can take 2 to 4 months for the timbers to completely dry.
Since the treated timber could be wet from inside, it can warp or get damaged during the period you are going to keep it for drying so keep them stacked on a flat surface with the help of stickers.
Read more about drying wood in this article where we also share how to accelerate this process.
2. Clean the Timber
Before you paint the wood, clean it properly to remove all the dust, stains, chemicals, etc. You can use steel wool or fine sandpaper or a mild detergent and scrub to do the job, depending on the condition of the wood.
Do not pressure wash it because that can end up thrusting a lot of water down the timber’s surface.
3. Apply a Coat of Primer
Before you start painting the wood in your favorite color, apply a coat of primer.
This is necessary for the paint to stick better on the timber’s surface and also to hide away the brown and greenish shade on the timber that comes due to pressure treatment.
Apply the primer evenly all through the wood where you intend to put the paint. Leave the primer to dry for a day (follow the instructions on the can) before you put the top paint coat.
4. Apply the Top Paint Coat
After the primer is dry, you can paint the wood with any color of your choice. But the point to remember is that you should apply a minimum of two coats of the paint separated some time for a refined finish and the color to come out well (check the drying time of your type of paint here).
The best paint for this purpose is high-quality latex (or water-based) paint. It has an exterior and interior version for outdoor and indoor purposes respectively (source).
What Types of Paint Can You Use on Pressure Treated Wood?
The paint that can prove to be the best for pressure treated wood is exterior latex paint (also called water-based paint) of the highest quality. But if the timber is going to be used indoors, you should use interior latex paint.
To hide away the brown or green shade on the timber, you should use a primer. If you do not apply the primer, a light color paint may take multiple coats to reflect itself fully. Whichever color you use, you should apply at least two coats apart from the primer. Do not put all the coats in one go, give a day’s break between the primer and for each coat over it.
Painting a pressure-treated wood requires more effort and patience than untreated timber. However, if you do the job carefully and meticulously, the final finish would look good and stay for a longer period of time.
How Long Should You Wait Before You Paint Pressure Treated Wood?
If the pressure treated wood is kiln-dried, you can paint it right away but if it is not, you should wait for it to be completely dry and that can take from 2 months to 4 months. Yes, you need patience more than anything else for this project.
A simple test to find out if the timber is completely dry or not is to put a few drops of water on it. If the water beads up, then the timber is not dry. But if the water gets soaked into the timber, it is completely dry.
Pressure-treated wood is not dry long after the treatment. Besides moisture, there is pitch, resin, and chemicals. They take time to work their way out of the timber. For a refined and lasting finish, this kind of timber needs to be completely dry before you apply the paints.
What Happens if You Paint Treated Wood too soon?
During the pressure treatment of timbers, a lot of chemicals are used that penetrate deep into the wood. The treatment takes place in a lot of water. So, the treated wood has chemical and moisture deep into its pores.
If we do not dry it thoroughly for about 2-4 months, it will still have moisture and chemicals that would try to come out as the timber dries out. If you have painted the timber before it is completely dry, the moisture and chemicals will remain trapped in the wood. It will damage both the painting and the timber itself. The moisture would lead to the warping of the timber and the chemicals in their process to evaporate peel off the painting.
So, painting the pressure treated timber before it is fully dry can have extremely negative fallout and not at all advisable.
Conclusion
As you have learned just now, pressure treated wood can be painted. However, this requires some patience, skills and the right type of paint and primer.
So, make sure you do not start your project head over wheels to avoid damage to your timber or furniture.