People often ask us if they can paint pressure-treated wood. The answer is usually yes, you can paint pressure-treated wood, but there are a few things you need to know before you start painting. In this article, we will share some tips on how to paint treated wood and what type of paint to use. We will also cover the best way to prep the surface before painting.
So whether you are repainting an old deck or want to give your porch a fresh new look, read on for our top tips on painting pressure treated wood!
What Is Pressure Treated Wood?
Pressure-treated wood is wood that has been saturated with one of the above chemicals to protect it. The chemicals used in the process are so high in concentration that they cannot be washed off easily with water or detergents.
Treated lumber is often referred to as green lumber because this type of lumber does not need to be stained, painted, or waterproofed for protection.
Process of Pressure Treating Wood
The wood is forced through pressurized chambers filled with the chemical solution to pressure treat wood. This process helps to penetrate the wood fibers evenly without leaving gaps behind.
The solution seeps into all parts of the wood, making it highly effective in protecting against fungal decay and insect infestation. Pressure-treating also increases the water-resistance and durability of wood. This process ensures that the treated wood is safe to use in many applications, such as decking, fencing, landscaping timbers, and poles for outbuildings such as sheds and gazebos.
The most common chemical used on treated lumber is CCA (Chromated Copper Arsenate), an arsenic-containing pesticide used to pressure treat the wood.
Other “chemicals” include ACQ or copper azole, becoming more popular than CCA. Other chemicals used include Alkaline Copper Quat (ACQ), Copper Azole (CuAz), Micronized Copper Quat (MCQ), and Oil-Based Alkaline Copper Quat (OBCQ).
Can you Paint Treated Wood?
Yes, you can paint treated wood. The painting will not seal in any chemicals from the treatment process – it only protects the surface from sun and water damage.
The main reason why people want to paint their decks is that pressure-treated lumber doesn’t hold paint very well and does even worse once installed. Lumber companies have known this for a long time, and an industry was created to address this issue. Lumber companies developed new methods to treat lumber to hold paint better. One such method is micronized copper azole (MCQ), which is applied in a liquid form and then baked into the wood.
Lumber treated with a micronized copper azole (MCQ) is preferred over CCA for many reasons. MCQ has no arsenic, chromium, or mercury and doesn’t pose the same health risks as CCA-treated lumber. It also won’t leach out chemicals into plant roots and soil-like CCA-treated lumber can.
How To Know If Treated Wood Is Ready To Paint?
Since treated lumber is pressure treated, you will want to clean it thoroughly before painting. A pressure washer can do the job nicely, or make sure to use a stiff bristle brush to get rid of any dirt or debris on the surface.
Knowing whether your wood is ready for paint also depends on what type of treatment the wood has undergone. If it is MCQ, you can paint as soon as the wood has been cleaned. CCA-treated lumber should sit for at least a year before being painted. OBCQ and ACQ can also be painted right after they have been cleaned.
How to prepare treated wood for painting
Once you have the material clean, the following techniques will help you prepare it for painting:
Scrubbing with water and dish soap – This method uses water to remove anything on top of the wood. To do this:
Mix one teaspoon of dishwashing liquid in a gallon of warm water.
Wet the surface thoroughly, allow the wood to sit for 10 minutes, then scrub the surface with a stiff-bristled brush.
Rinse it thoroughly with clean water and let it dry before painting.
Using a primer – Whether you are painting CCA-treated lumber or pressure-treated lumber painted in the past, using an oil-based or alkyd primer will help you get the coverage you need.
Cleaning with mineral spirits – Mineral spirits can also clean wood surfaces for painting, but it takes more time than using dish soap and water. To do this, soak a rag or sponge in mineral spirits and cover the surface. Allow it to sit for 10 minutes before wiping off.
Pressure washing – If you have a pressure washer, it is possible to use that instead of dish soap and water. Use low-pressure settings on your washer and follow the same process of allowing surfaces to dry before painting.
Sanding or scraping – This method will help remove any wood debris before using a primer or dish soap and water.
How to Paint Treated Wood Step by Step
Step 1: Make sure that your wood is clean. You will want to use a power washer or stiff bristle brush to remove any dirt, debris, or loose paint from the surface.
Step 2: Check for rot and repair as needed. This would include areas with soft spots, mold, mildew, etc. If it needs repairing, be sure to make the repairs before you paint.
Step 3: Use a high-quality exterior primer, such as Zinsser Bullseye 1-2-3 or Kilz Professional Latex Wood and Deck Primer Sealer. You want to use a primer that will seal in any previous stains, dirt, or other contaminants that may have been left on your wood.
Step 4: Use an exterior paint that is made for pressure-treated wood, such as the Sherwin Williams Emerald® Exterior Paint and Primer in One or Benjamin Moore Regal Select® Semi-Transparent Waterborne Exterior House Paint.
Step 5: Apply at least two coats of paint to protect your treated lumber from the elements.
How long does treated wood take to dry?
Treated lumber takes a long time to dry. If you paint within six months of treatment, the chemicals could continue to leach out and cause problems. The best thing you can do is wait a full year after pressure-treating before painting.
Additionally, treated lumber needs to sit for at least 24 hours after you paint it before it can be exposed to rain.
Finally, if you paint CCA-treated wood and it is still wet, the pigment in the wood can separate from the chemicals. This causes a whitish appearance that looks unappealing and may even be unsightly enough to require another coat of paint to fix.
How can you speed up the drying process of treated wood?
If you don’t want to wait for lumber to dry, there are steps that you can take to speed up the process.
- The first thing you can do is increase airflow by opening windows and doors. However, you must be very careful if it is warm out because the heat will cause wood to dry more slowly and increase moisture content.
- This will also increase the chances of mold and mildew growing on your wood, which can cause more damage than waiting for the lumber to dry.
- Instead, you should use air conditioning or dehumidifiers if it is warm out. If you use a dehumidifier, make sure that it is very well maintained to prevent mold growth and fungi.
- If you are using an AC unit, be careful that it is kept clean to avoid any problems associated with black mold or other types of fungus.
What paints are best for treated lumber?
The type of paint you use for treating wood depends entirely on the lumber that needs to be painted.
For CCA-treated lumber, choose an exterior alkyd or oil-based enamel. Be sure to test these products first in an inconspicuous area to ensure that they adhere to the wood and can be scrubbed off with soap and water if necessary.
Pressure Treated wood
For pressure-treated wood that has already been painted, use an oil-based or alkyd enamel catalyzed with methylene chloride. These paints are also scrubbable, so you don’t have to worry about them peeling away from wood.
How to take care of Painted Treated Wood?
- To care for painted, treated wood, you must first reapply a fresh coat of paint every two to three years. This is because the pressure-treated lumber will continue to leach out, making it necessary for fresh layers of paint.
- Mildew growth and algae can also be a problem and may require that you use a solution of bleach and water to scrub the wood clean.
- If mildew grows on pressure-treated lumber, it is necessary to remove all dirt and grime and any loose pieces of paint before applying an anti-mildew sealer. Otherwise, the growth will continue to harm the wood.
- In addition, if your paint becomes chipped or faded with time, avoid using harsh chemicals such as TSP-PF or muriatic acid to scrub it off. These chemicals can cause problems if they directly contact the CCA-treated wood, causing a slight green discoloration that will need to be painted over.
What are the benefits of pressure-treated lumber?
- The biggest benefit of pressure-treated lumber is durable, strong, and long-lasting.
- Compared with regular lumber, treated wood can last two to three times longer. The pressure treatment will keep the lumber from rotting or cracking over time, no matter what weather conditions your deck endures.
- Pressure-treated lumber is also widely available at a variety of locations. Most hardware stores, lumber yards, and home improvement stores will carry multiple types of pressure-treated lumber to accommodate the needs of their customers.
- In addition, because it is so widely used, you can find many different types of paint specifically designed for coating CCA-treated wood. This allows you to waterproof, decorate, and protect your deck or other outdoor structure until it looks new.
Can you stain pressure-treated lumber?
Yes, you can stain pressure-treated lumber. However, there are a few things that you should keep in mind when staining this type of wood.
First, it is important to be aware that any chemicals or solvents directly applied to the surface will damage the CCA-treated wood and must not be used.
Secondly, you must use a stain with an oil base to avoid damage.
Lastly, pressure-treated lumber will have a unique smell when it begins to dry out after being stained. This is perfectly normal, and the wood should not be alarmed.
You can paint on pressure-treated wood. Choosing the right paint for CCA-treated wood is important to avoid any problems. Make sure that you are using an oil-based or alkyd enamel when painting the lumber so it can be scrubbed off if necessary.
Also, pay attention to any mildew growth and scrub away grime before applying a finish to prevent future growth.
Frequently Asked Questions: Paint pressure treated wood
The best primer for pressure-treated wood?
The best primer for pressure-treated wood will be a primer designed to stick to CCA-treated lumber. It should also possess a high level of adhesion while being easy to clean up while still resistant to peeling or flaking off the treated wood.
What happens if you paint pressure-treated wood too soon?
If you paint pressure-treated wood too soon, the moisture from the lumber will not have time to evaporate. This means that the pressure-treated wood will remain wet and cause a chemical reaction.
What happens if a treated board is left out in winter?
If a treated board is left outside during winter without being covered, it can soak up water and freeze. The expanded ice may cause the board to warp, split, or even crack.
What types of paints can I apply to pressure-treated wood?
You can apply virtually any type of paint to pressure-treated lumber. Just make sure not to use grit sandpaper on any exterior paint. If you are planning to leave the surface without painting, make sure it has been treated with primer or stain first.
When applying paint or other finishes, keep in mind that there are many types of paints designed for use on CCA-treated wood. These paints are typically oil-based or alkyd enamels while being easy to clean up while still being resistant to peeling or flaking off of the treated wood.
How do you tell if pressure-treated wood is dry?
To tell if pressure-treated wood is dry, lightly sand the surface, and if the wood dusts away easily, then it’s ready to use. If there is still dust on the wood after sanding, you should wait for it to dry further.
What happens when treated lumber gets wet?
When treated lumber gets wet, there is a chance that some of the chemicals can be released into the surrounding environment. To maintain safety, ensure that treated lumber is dried before being used again to avoid contaminating your surroundings.
Is it Safe to Paint Pressure-treated Wood?’
Yes, it is safe to give pressure-treated wood a coat of paint. However, you should make sure that the surface has been sanded lightly and then cleaned with a cleaning solution before being painted to remove any dirt or other loose particles from the surface.
Is it better to stain or paint pressure-treated wood?
Staining pressure-treated wood is a good option if you want to change your deck’s color or other outdoor furniture. However, it is important to remember that any chemicals applied directly to the surface will cause damage.
What is the green stuff on pressure-treated wood?
The green stuff on pressure-treated wood is a form of algae. It feeds off the chemicals used to treat the lumber, so removing it will help prevent future growth.
Does the treated wood deck need to be painted?
Yes, your pressure-treated wood deck should be painted. Using a paint designed for CCA-treated lumber will help prevent the wood from becoming weathered and discolored and protect against mildew growth.
What happens if you don’t prime pressure-treated wood?
If you do not prime pressure-treated wood, it can cause the wood to warp, crack, or split. The chemicals used in pressure-treated wood are sensitive to sunlight, so they must be protected by a primer.
What is the difference between green and brown treated wood?
Green treated wood refers to untreated lumber, while brown treated wood is your typical pressure-treated lumber. Both green and brown pressure-treated woods can be painted or stained.