How To Paint Pressure Treated Wood(Why Everyone is Wrong)

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I get asked that question a lot.

A homeowner will search the internet for answers, and all they come up with are confusing and conflicting articles.

At the end of their search, they still don’t know How to Paint Pressure Treated Wood.

The important thing is to get it right. Getting it wrong is expensive! You don’t want to have issues six months after you’ve painted because you were following the wrong advice.

There are a lot of unanswered questions out there about how to paint pressure-treated wood.

Sit back and relax as I walk you through everything you need to know and what most people are getting wrong.

Ultimately, you’ll have the information you need to get it right, potentially saving you thousands of dollars.

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What is Pressure Treated Wood?

  • Pressure-treating is a process where lumber (Pine, Spruce, and Fir) is immersed in a chamber that vacuums the air out. Then the chamber is flooded with chemicals, and pressure is added that forces the solution into the wood.
  • The chamber then vacuums out the excess solution and air. The lumber is then placed on drying racks, and the but ends are labeled to identify the process that was used.
  • The chemicals are a combination of preservatives and fire retardants. The preservatives contain forms of copper (MCA, CA-C) and Borate. Copper has long been used to deter insect infestation. If you’ve ever seen a Cedar Shingle roof, copper strips are installed near the peaks, and rain run-off carries the copper to all areas of the roof.

What Types of Pressure Treated Wood are there?

Pressure-treated wood has two categories, Above Ground and Ground Contact.

Ground Contact lumber is injected with more chemicals and is used in applications where it’s difficult to maintain or replace.

  • Above Ground lumber is used where the application is at least 6 inches above the ground, has proper ventilation & drainage, and can be easily maintained or replaced.
  • Ground Contact lumber is used in applications 6 inches above ground or less but can also be used above ground.
  • Pressure-treated wood comes in different grades. Higher grade lumber has a better appearance and fewer knots. A lower grade is used when appearance is not an issue. Keep in mind that as the wood dries over time, lower-grade lumber tends to warp and split, and that’s where protection comes into play.
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What is Pressure Treated Wood Commonly Used For?

You should only use pressure-treated wood for exterior applications.

The most common uses for PT wood are;

  • Decks & Porches
  • Fencing
  • Freshwater Docks
  • Structural framework

How do you protect Pressure Treated Wood?

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This is where a lot of the confusion occurs. Pressure-treated wood is designed to withstand the elements; therefore, it needs less maintenance.

However, depending on the application, Pressure-Treated wood should be protected to prevent cupping, warping, and splits.

Decks and Fences are the two most popular applications where pressure-treated wood should be protected.

They are in the elements, constantly beaten by wind, rain, and sun, and are at the most risk for degradation.

There are three ways to protect pressure-treated wood; Painting, Staining, and Clear coating. I will explain the advantages and disadvantages of each.

Painting

  • Product selection is important when considering how to paint pressure-treated wood. There are tons of products on the market, and they all claim successful outcomes. Consider that it’s not always the paint that’s the issue; it’s the process.
  • There are many types of paint, but not all are recommended for decks and fences. Acrylic latex top coats have excellent adhesion and color retention and are widely used. Oil-based paints and not a good choice for decks because they lack the elasticity of latex and tend to peel more rapidly.
  • A good primer is needed in either application before the finish coat.

Staining

  • Like paints, there are a variety of stains available in many finishes and transparency. Oil Stain finishes are transparent, semi-transparent, and semi-solid. These finishes have different levels of transparency and allow the wood grain to show through. Colors are somewhat limited. Oil stains require paint thinner to clean tools and splatters.
  • Latex-based stains come in a wide range of colors and are easy to apply. Because they are a stain and not paint, they are applied directly to the wood without needing a primer. They have a look and feel of regular paint but are better suited for decks. Products like Sherwin Williams SuperDeck Exterior Waterborne Solid Color Deck Stain have over 100 available colors and have a “Cool Feel Color Technology” that reduces decking surface temperatures by 20%.

Clear Coating

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  • Clear coats are extremely popular because they are easy to apply and have a more significant margin for error. A clear finish protects the pressure-treated lumber from the elements and won’t cover up the beauty of the wood. Clears come in oil and latex.

What’s the Best Paint for Pressure Treated Wood?

The best paint for pressure-treated wood is no paint at all.

Latex stain is the best product for pressure-treated lumber, especially on decks and fences.

Latex stain is the way to go if you’re looking to save money and a few steps.

Stains are self-priming, which eliminates a costly step.

Pressure-treated wood is full of knots that need to be “spot” primed with a specialized shellac-based primer to prevent bleeding through the finish.

That’s another step eliminated.

Are you smelling the savings?

Most articles you read will tell you to prime, spot prime, and apply two coats of finish. That’s a total of 4 steps.

With latex stain, you apply one coat for semi-transparent and two coats for solid. That saves you two things; Time and money! Something we all need more of.

Applying paint takes four steps to complete the job. That means there are four chances for something to go wrong if not done correctly.

Latex stain is self-priming and seals in knots. It comes in various colors and cleans up with soap and water.

Diy or Hire a Pro to Coat Pressure Treated Wood?

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It all depends on the situation as to whether to DIY or hire a pro.

If you are doing small projects like walkway borders or posts, then you can handle it. If you’re tackling a deck or a few hundred feet of fencing, you must weigh the pros and cons.

Pros

  • Professionals have done the work many times and have a process they adhere to that saves time and money.
  • Results have a guarantee of some type of limited warranty on their work.
  • Pros already have the tools and equipment to get the job done.
  • You get professional results.
  • If something goes wrong, it’s on the pro, not you.
  • Hiring a pro frees up your time to focus on other projects.

Cons

  • Hiring a pro can be expensive when a lot of labor is involved.
  • Companies have overhead that they add to their pricing.
  • Sometimes hiring a pro is a gamble if they don’t have work samples or references.
  • You have to wait on their schedule. If a pro is busy, your project may get pushed back to the following year.

What do I Need to Paint Pressure Treated Wood?

I will use “painting a deck” as an example to learn what you need to paint pressure-treated wood.

Check the Weather

You need a window of 24 hours before and after you start the project where there is no threat of rain.

Painting Equipment

  • Drop cloths (can be made of paper and disposable)
  • Paint brushes
  • Roller trays and paint pots
  • Roller frame and sleeves
  • Pole or broomstick to roll the floor
  • Knee pads
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How to Paint Pressure Treated Wood

Coating a pressure-treated deck is a process and must be done correctly to avoid issues down the road.

Most professionals don’t give a year warranty because the finish is not only in the elements but walked on and is subject to heavy furniture and grills.

The process is not that difficult but must be followed. No shortcuts.

Make sure the wood is completely dry.

Pressure-treated wood is wet when purchased. The lumber must be allowed to weather and dry for several months.

A simple wood moisture meter is an inexpensive tool to measure the moisture’s density.

Some products require less than 15% moisture content for proper application. Sherwin Williams products can be applied to wet wood in some instances but need less than 25% moisture content.

If the wood was “Kiln Dried,” there is no need to wait, but you should still check the moisture density. 

General Tools Digital Moisture Meter.

Clean the Wood

Ensure the wood is cleaned with a solution of one part bleach to three parts water.

Scrub the surfaces with a stiff bristle brush and rinse thoroughly—wet surrounding bushes and grass before cleaning and rinse afterward.

Be sure to wear protective gloves and eye covering.

Allow the wood to dry completely.

A power washer can be used to clean the wood, but it has to be done correctly.

You must follow with the grain of the wood, and each board must be power washed from end to end individually.

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Proper Technique

Now that the wood is dry and ready to be coated, proper technique is critical for ensuring the best possible results. Again we’ll use a deck as the example here.

Start with the “fencing” surrounding the deck (railings, posts, and spindles).

One person on the deck and the other outside, working together. If at least two people work on the project together, it will save time and frustration.

Work from left to right and begin by painting the spindles from top to bottom.

Each person applies the finish to two sides of the same spindle (the side facing you and the side to the left). That way, both people paint the entire spindle on all four sides. Inspect your work when the section of spindles is complete.

Look for drips and sags in the finish and brush them out flat.

Go back to the beginning of the fence section and paint the bottom and top shoe molding.

Make sure there are no missed spots, especially under the handrails.

You finish off each section by painting the top rail and posts.

Repeat with the other sections.

Carry a damp rag to wipe drips on the deck floor.

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The next step is the deck floor.

Start on the deck board next to the home’s sidewall.

It is possible to roll the floor, but it must be done quickly and from end to end.

Working together, paint 1–2 boards each, from one end to the other.

When working in direct sunlight, each board should be brushed. Make sure you coat the sides of each board for complete coverage.

The stain will dry incredibly fast.

When you reach the mid-point of the deck, begin the application on the farthest board and repeat the process.

Stop when you are within a few boards of the completed section of the floor.

Then, paint your way “out” of the deck from the farthest point to the stairs or exit point.

Do not let the stain puddle.

Complete the deck by coating the exterior side skirt boards, posts, and stairs (if any).

If a second coat is needed, follow the specifications on the can.

The product will not be warrantied if the instructions are not followed.

Let the first coat dry properly (if applying a solid finish) before painting the second coat.

What not to do

Do not attempt to “cut” in all the floorboards’ sides and then roll it out. You will end up with a sloppy-looking finish and lines on top of the boards closest to the edge that will not match the finished roll.

Not following the correct technique could result in repeating the process.

That is a waste of time and money.

Do not use one can of product at a time. Be sure to “box” or mix all of the products and stir frequently.

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Can you spray Pressure Treated Wood?

The short answer is yes; you can spray the finish coat.

You must add a few more steps to prepare for this process. The entire perimeter of the deck must be covered in drop cloths.

If the drops are left on the grass too long, it could result in the “burning” of the lawn.

You also need to pay attention to where the overspray of the stain will end up.

Most airless sprayers have a psi of 2800 or more! That could potentially spell disaster if done improperly.

When using a paint sprayer, it’s crucial to back brush everything that gets coated to get a consistent finish.

How to Maintain Pressure Treated Wood

The applied finish coat is how to maintain pressure-treated wood.

Once a top coat is painted, the product protects the wood from the elements and fungal growth.

  • Clear coats are fine but should be re-applied after 1–2 years for the best protection.
  • Wash the deck with mild deck cleaner before and after the “decking season.”
  • Keep a bucket of warm, soapy water handy when grilling on the deck to wipe up grease and spills.
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Now You Know How to Paint Pressure Treated Wood

When you started, you didn’t know everything about pressure-treated wood.

Who does?

You may not have known the process used to create it, but now you do.

You may not have known the different types and grades of pressure-treated lumber, but, You do now.

With the knowledge you’ve gained from someone with over 30 years of experience, you can be confident when deciding how to paint pressure-treated wood and maintain the beauty and value of your home.

Plus, with the instructions on how to paint pressure-treated wood yourself, you’ll save thousands of dollars too!

You can take that to the bank! Literally.

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