Can you Paint Pressure-treated Wood Deck or Fence?

Is it safe to paint your pressure-treated wood?
Paining pressure treated wood

I’ve had a lot of questions about painting pressure-treated wood and I thought it would be best to answer them all in one post. 

The first question is: “Can you paint pressure-treated wood?

The short answer, yes. Pressure-treating the wood makes it durable, which is ideal for outdoor projects including outdoor furniture. Just keep it away from having direct contact with the soil, as this, together with your edible plants may absorb the chemicals, putting people at risk. 

But first things first…

What is pressure-treated wood? 

Pressure-treated wood is a type of lumber that has undergone special processes to make it more durable and less susceptible to insect infestation, mold and decay.

These treatments can even make the wood fire-retardant.

There are three main types: 

  1. An oil finish (made with chemicals such as Copper azole (CA), or copper quaternary (ACQ))
  2. Paint over the top urethane layer which creates its own protective coating – this process requires more maintenance but provides long lasting protection from water damage.
  3. Ethanly coated pressure treated (“EP”) boards made out of recycled materials such as plastics 

Can you Paint Pressure Treated Wood?

Yes! You can paint pressure-treated wood. But, if the lumber has been chemically treated with chromate copper arsenate (CCA), surface-treat it before applying paint. Use oil-based acrylic instead of water-based paints or stains because the chemicals in the treated lumber are sensitive to water-based paints.

Why is painting pressure treated wood the best option?

Looking at the treated wood, you may feel there’s something missing. it looks dull, plain, and worse, uninviting. 

This can be expected as pressure-treated wood usually comes in green, tan, brown, dark, and natural wood color.  It is most common that treated wood has a greenish color, so better to paint pressure-treated lumber or stain it, than to just let it be.

Paint will not only give it a pop of color but also provide an extra layer of protection from elements. The odor of certain paints also repels insects. Plus, paint protects the wood from dust and moisture. 

Sure, some websites advise against painting treated wood and instead suggest you stain pressure-treated lumber. This is because of the poor output when varnish or multi-coat paint is used.

But by following the steps below, you’ll get to paint pressure-treated wood properly, bring more life to your project and achieve a great finish. 

How to Get Pressure Treated Wood Ready for Painting

Preparing pressure-treated wood before painting it can help prolong the life of your project. Here’s a quick guide to get you started:

1. Allow Treated Lumber to Dry Completely

Making sure that your wood is dry is the first step on how to paint pressure-treated wood.

Even if the wood has been under direct sunlight, don’t begin the painting process immediately. From the hardware store, treated wood is considered wet. Nor is it dry after you have installed it on your porch or deck. Check out the best paint for your porch.

The moisture comes from the chemicals used in the pressure treatment process. So, let the treated lumber properly dry for three to four months.

And just a word of caution. Even though you must give the wood time to dry, don’t over-dry it. If this happens, the over-dried wood would crack. So, check the wood surface for moisture periodically.

Now, How will you know When the Wood is Completely Dry? 

  • Touch the wood to feel if it’s dry.  
  • If you’re unsure, perform the water test. Sprinkle some water on it. If the wood absorbs the water, you can start painting. But if you find water beads, wait a little more. Repeat the water test and make sure no water beads form and the wood is dry.

How to Speed up the Drying Process

Given that it takes too long to get it to dry, is there a way to cut the drying time?

Sure, here are two quick tips;

  • Pile the wood in a crisscross pattern to allow it to air-dry.
  • And if you don’t have much time in making sure your treated wood is dry, use kiln dried wood. This kiln dried wood is dried in an oven, faster than if it’s air-dried. This makes kiln dried lumber ideal if you’re pressed for time.

2. Clean the wood

When you’re sure the wood is completely dry, clean it before painting. Use a stiff brush, mild detergent and water to remove the grime and debris. Soapy water is better than using a pressure washer. 

Don’t use a power washer as the high pressure may remove the chemical preservatives or force water into your wood fibers.

Again, wait for the wood to completely dry. Sadly, this may take several weeks.

To be certain if the wood is dry, you can measure moisture content by using a moisture content meter on the surface.

How to Paint Pressure Treated Wood

But before you start painting pressure-treated wood, it’s best to have the necessary tools ready. This way, you will save time and energy.

Materials and Tools

  1. Primer
  2. Latex paint – have at least enough for two coats
  3. Paintbrush
  4. Brush for cleaning the wood
  5. Mild detergent 

Step by Step Painting Process

Since the wood is now ready for paint, let’s get right into it.

Step 1: Apply high quality latex primer.

You may ask, “why is applying a primer so important?”

This is because latex primer helps the paint adhere to the wood’s surface. It also stops the pressure-treated wood from absorbing the top layer of paint.

The first step is to ensure your primer is suitable for outdoor use and that it is intended for pressure-treated lumber. Avoid using an oil-based primer if possible.

it’s better to use a brush on the wood surface instead of a paint sprayer. This will ensure the paint adheres and is applied evenly and thoroughly.

Step 2: Apply high quality exterior latex paint.

Apply at least two coats of latex paint thoroughly. Why two? The first coat of paint will last about six months, but for a long-lasting finish, you should apply two coats.

Latex is the best paint you can use on treated lumber. Don’t forget to let the first layer cure before painting the second coat. 

Note that curing usually takes a whole day. 

Exterior latex paint is better than oil-based paint, as it’s also known as water-based paint. It is better at adhering to smooth wood surfaces. Altogether avoid using oil-based paint.

As you paint, remember that horizontal surfaces on your project are more exposed than vertical surfaces. And it’s best to follow the manufacturer’s recommendations to obtain an excellent finish. 

Step 3: Apply a water repellent finish.

After applying water-based paint, you can proceed to apply a water-repellent finish with an ultraviolet stabilizer. This will prevent the paint from fading or changing on the surface.

That’s it! I bet your deck feels new and inviting.

For additional protection, you can also stain pressure-treated wood even after painting it. Stained wood gets more protection against damage and decay.

How to Maintain of your Painted Lumber

Of course, given that your fence or deck is exposed to the elements, particularly direct sunlight, are there ways to maintain the paint on your pressure-treated wood?

The common concerns on painted treated wood are  1) mildew growth; and 2) ultraviolet protection and 3) shrinking and swelling;

Mildew growth

Can you Paint Pressure Treated Wood image

Water and organic matter are catalysts for mold and mildew. To make sure that water doesn’t get stuck on the wood. Plus, you should have adequate ventilation between boards (if you decide to install a deck with your treated wood) and underneath the surface, so water won’t get stuck in the wood.

Solution: use mildewcide.

On the other hand, you can use a  five-way tool to remove molds. If there are still remnants, you can apply an exterior wood cleaner mixed with warm water.

Wait at least an hour to dry. To prevent molds from reappearing, you can spray a wood-safe fungicide. Then leave it to dry under the sun.

Ultraviolet ray protection

For this, an outdoor wood sealer that has a water repellant and ultraviolet stabilizer will suffice. Apply this after cleaning your deck or porch.

You also have to clean your project regularly. With this, your paint will keep its quality for two years.

Shrinking and swelling

Shrinking and swelling naturally occur when the wood is exposed to direct sunlight.

Wood shrinks when it dries out. This is why it’s advisable not to leave gaps on the boards when installing a deck.

Expect to see cracks in six to 12 months as the board gradually dries up.

This is the advantage of using kiln-dried after treatment or KDAT lumber, as it will not shrink significantly. Moreover, klin dried after treatment lumber’s initial look will last for years.

Swelling, on the other hand, occurs when the wood is soaked in water. To prevent swelling caused by water soaks, it is best to apply sealant between the gaps every year.

Can you stain pressure treated lumber?

Yes, you can stain pressure-treated lumber. Staining pressure-treated wood is a great way to add color and protection to your deck. There are two methods for staining: 

  1. Spraying
  2. Brushing on the stain. 

Spraying has its benefits because it’s quick and easy, but you have less control over how much goes where. Brush-on stains give you more control, but they take longer since each board needs to be individually coated in the liquid finish. 

When using either method, make sure that all surfaces of the wood are covered with an even coat of oil-based primer or paint before starting so that no raw wood is exposed to air, water, dirt and other elements which will cause premature decay.

In short, you can either choose to paint or stain.

Advantages of pressure treated wood

Here are the pros and cons of pressure-treated wood.

Pros

Unlike regular lumber, pressure-treated wood is more dependable – will not have insect damage, is resistant to moisture, and even fungi. And if you add fire-retardant chemicals, it can even resist fire.

Moreover, this type of wood is more affordable than using cedar or redwood. This will also save you from the cost of repairs. And in case you need to have it repaired, it will not cost a pretty penny.

Cons

But of course, using and painting this type of wood has its downside. In time, you can spot splinters on the painted wood, as it is continuously exposed to natural elements and changing temperatures.

You can also expect to have checking, wherein the painted wood dries out after around six to twelve months.

This happens again because of the moisture and extreme heat bearing down on the wood. The sun’s rays will not only make the wood dry but also cause the paint coat to fade. Thus, they say it’s better to stain pressure-treated wood.

Moreover, treated wood should not be burned, trimmed, or cut, Doing so can release harmful toxins.

Tips in using pressure treated wood

  1. Attach boards bark side up.
  2. Put pilot holes on the edge of the board when using a screw.
  3. Should the wood become wet, butt deck boards together.
  4. Use the right fasteners.
  5. Do put a gap between boards.
  6. Use a dust mask and eye protection when working on the wood.

After cutting the wood, apply a wood preservative to seal end cuts.

In installing fences using pressure-treated wood, best to use water-repellent sealers/preservatives that contain a mildewcide.

Pressure-treated wood is durable but you should inspect your fence at least once a year. Replace broken boards and check the nails and screws’ condition.

In case there are cracks, you can use waterproof wood glue. Also make sure that you clean your fence every three years so that you can remove the dirt or any mildew that has developed.

In case you have decided to install a deck, you can use a water-repellent sealer or a penetrating semi-transparent exterior stain to get the best finish.

FAQs

Best primer for pressure treated wood 

Well, there really isn’t one primer because everyone has their preference. The best primer for pressure-treated wood is one that will not only make your deck or fence look brand new, it’ll also protect them against future decay and rot. Here are some options for quality primers.

When is the best time to paint treated wood?

You should paint pressure-treated lumber after allowing it enough time to dry. The best time for pressure-treated wood to dry out completely is 8 weeks after treatment. But if you live in a humid climate it may take up to 18 months for the wood to fully air out before cleaning it. Don’t paint wet wood. The best time, therefore, is after it’s completely dry and clean. 

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

Painting treated lumber too soon will cause warping due to excess moisture content. It’s always important to let pressure-treated wood dry before painting it. This will ensure that your paint job lasts as long and you don’t end up with an uneven surface or peeled-off finish.

How do you tell if pressure-treated wood is dry?

The best way to make sure pressure-treated wood is dry is to use a moisture meter. It’s an inexpensive tool that can be used on outdoor lumber, too. Moisture meters are also sensitive enough to tell the difference between wet and dry areas of your deck or porch. 

What types of paints can I apply to pressure-treated wood?

The best paints for pressure-treated wood are the ones that will last. There are three types: exterior enamels, interior paint and stain or penetrating oils like linseed oil and tung oil.  These paints penetrate deep into a surface’s pores; they also have more aggressive drying times so you won’t end up with blisters on your hands from working too quickly when spraying them around in an open workspace

How long should I wait to paint pressure-treated wood?

Wait at least six months before painting pressure-treated wood. This will give the chemical treatment time to work its magic and penetrate deep into the pores of surface fibers.

It may seem like a long time but don’t worry; you’ll get better results once the lumber is fully dry.

Conclusion

The answer to this question  “Can you paint pressure treated wood” is a YES, but you must be careful about what type of paint you use.

Pressure-treated wood is often used for projects where the surface will be exposed to moisture. 

And learning how to paint pressure-treated wood will make your home feel like it’s new again. 

Read on below if you’re interested in understanding all there is to know about keeping your outdoor great.

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