When is Pressure Treated Wood Ready to Paint?

painting pressure treated wood

Are you wondering if your pressure-treated wood is ready to paint? How long should you wait before it’s ready? In this article, I’ll cover everything from when you should and shouldn’t paint pressure-treated lumber. 

Pressure-treated wood needs to be dry before painting. To determine if your treated wood is paintable, drop some water on the surface of the board. If the water soaks into the wood, then it’s ready for paint. However, if the water beads on the surface, then the wood is still too damp. 

After the wood is pressure treated, it can be moist for quite a while. The moisture can make the wood difficult to work with, causing the wood to shrink and warp as it dries. 

The moisture also makes it difficult to paint. 

In the sections below, we will discuss how to tell when pressure-treated wood is ready to paint. 

When Is the Best Time to Paint Pressure Treated Wood? 

You should paint pressure-treated wood after it is clean and dry. While pressure-treating the lumber, water is used to introduce chemicals deep into the woods’ fibers. 

As a result, the wood is extremely wet when it comes out of the treatment chamber. Depending on the thickness of the wood and the type of treatment, it can take several months for the treated wood to become dry enough for painting. 

Here are several factors that affect the dryness of the wood: 

  1. When it was treated 
  2. Where it is stored 
  3. The thickness of the wood 
  4. Whether the wood was kiln-dried. 

Let’s look at these in a bit more depth. 

Pressure Treated Wood Time Since Treatment 

If you can, ask the manager at your lumber yard how recent the pressure-treated wood came into the store. Figuring this out may give you a general idea if the wood has had time to dry. 

However, there are more factors in play. Unfortunately, treated lumber is often stacked in tight bundles at the hardware store. These tight stacks are not conducive to equal dry times. As a result, you’ll find some boards that are drier than others.

This idea leads us to our next topic. 

Consider Where Pressure Treated Wood is Stored 

If pressure-treated wood is stored in a cool, dark place, it will take much longer to dry. Maybe you don’t need the treated lumber right away. It will last, right? 

Well, sort of. Yes, the pressure-treated wood will still resist rot and insects; however, it can still be affected by mildew

On the other hand, you might store your wood in a dry, warm environment. While this will help your lumber dry faster, it can also create problems. When pressure-treated lumber is exposed to high heat, there’s a greater likelihood of the wood becoming warped. 

When you’re assessing your treated lumber for painting, consider where it was stored.

Consider the Thickness of Treated Lumber Affecting Dry Time 

If you’re familiar with treated lumber, then you know that you can pressure treat almost any type of lumber.

Sheets of plywood or fencing will be thinner than a two-by-six. As a result, you can expect the thinner treated lumber to be ready for painting before the thicker lumber. 

Kiln Dried Treated Lumber 

Some treated lumber is kiln-dried before it is sold. Basically, a kiln is a large heater that bakes all the moisture right out of the wood. The kiln does this in a controlled manner that reduces the amount of warping. 

If you need lumber that is ready to paint the right way, look into purchasing kiln-dried treated wood. It will be more expensive, but it might be right for you if you need to get that project done fast.

Alright, now let’s go into several other ways to determine if pressure-treated lumber is ready for paint.

How do You Tell When Pressure Treated Wood is Dry? 

This section discusses several ways to know that your treated wood is ready for paint. 

Here are several ways to know pressure-treated wood is dry: 

  1. Feel test 
  2. Water test
  3. Digital test 

Let’s look at these options in more depth. 

Feel Test for Pressure Treated Wood 

For this test, you look over the wood and use your sight and feel to determine if the wood is dry. If the wood fails this test, you don’t need to waste your time with the next two tests. 

Using your hand or a paper towel, press into the wood and see if you can detect moisture. Very wet wood will ooze out moisture, similar to a sponge. 

However, know that this test can only determine that your wood is still wet – it will not prove that the wood is dry and ready for painting! 

Wood is very absorbent and is essentially a large sponge – this is one of the reasons it takes so long for it to dry! 

Water Test for Pressure Treated Wood 

If you don’t detect any moisture in the first test, there’s another way to determine if your wood is dry. 

Take a cup of water and place several drops of water on the surface of the wood. If the water soaks into the wood, it means that the wood is dry enough for painting. However, if the water beads on the surface, there is too much water within the wood. 

Now, maybe part of the wood is dry enough, but is the whole board? Dousing the whole board in water would be counter-intuitive – so what do we do? 

I’ll share a solution in the next section. 

Digital Moisture Tester for Treated Lumber 

The final way to test the moisture content of your treated lumber is to use a digital moisture meter.

The digital moisture meter has two prongs you press into the wood, testing the moisture content.  

If you use a digital moisture meter, be sure you have the device properly calibrated. Also, test more than one spot on the board and average the amounts you get. 

Alright, now let’s discuss what happens when you paint pressure-treated wood too soon. 

What Happens if You Paint Pressure Treated Wood too Soon? 

Pressure-treated wood contains a high level of moisture after it is initially treated. Unless your treated lumber was kiln-dried, it would likely be damp when you buy it. 

I always advise waiting until the treated wood is dry before you paint. If you paint too soon, you won’t get a quality finish. 

Here’s what happens when you paint pressure treated lumber before it’s ready: 

  • Your paint won’t get dry properly 
  • Paint is likely to peel 
  • Your board could warp 

Below, we explore these possibilities in more depth. 

Paint Won’t Dry on Damp Treated Lumber

If you paint pressure-treated wood before it’s ready, you’re essentially locking moisture within the wood and giving it nowhere to escape. While this can create chipping and peeling, it can also cause the paint not to dry. 

Since the board is still damp, the moisture will wick into the paint and prevent it from properly curing. Paint that isn’t dry is a liability for several reasons. 

First, it is more likely to become damaged while it’s drying. Since the paint hasn’t hardened, the soft surface is more likely to sustain dents and scuffs. 

Second, the paint won’t take on the color you want. The paint looks the way it’s supposed to look when it’s properly dry. 

Your Paint Will Peel 

When you paint over treated wood that isn’t dry, you don’t allow your paint to adhere properly to the wood fibers. As a result, you get paint that begins to flake much sooner than if you had allowed the wood to completely dry. 

When a board dries, it naturally becomes a bit smaller in size. This slight shrinking of the wood will further accelerate peeling paint. 

And then what happens? That’s right; you have to use a sander to remove all the old paint and start all over. 

Your Board Will Warp 

As we said in the last section, wood will shrink slightly as it dries. This shrinking is also how a board begins to warp. When one side of the board shrinks faster than the other side of the board, the board will begin to pull towards the shrinking side. 

If you paint treated lumber before it’s dry, you cause the non-painted side to dry faster. And when one side dries faster than the other, you get warping. 

You’re better off waiting until the wood is dry; otherwise, you’ll end up with warped wood, peeling paint, and a big project. 

Final Words on When to Paint Treated Wood 

The main thing to worry about when painting treated wood is ensuring that the wood is dry. 

To figure out if the treated lumber is fully dry, consider where the wood was stored, if it’s been kiln dried, and the thickness of the board. 

You can test the moisture content by dropping several beads of water on the face of the board; if the water absorbs, then the board is ready for paint. 

Painting treated wood requires patience. If you rush the process, you’ll end up with more work down the road.