So, you have just gone out and bought some pressure treated wood for your new outdoor project whether that be a new fence or deck etc, and now you want to color it so that it matches with your garden’s vibe. You may be wondering if it’s fine to paint it or just stick with a regular stain.
In short, you can paint pressure treated wood as long as you keep it away from any soil where you will be growing edible plants, as the chemicals from the pressure treatment can seep into them and thus make it dangerous for human consumption.
We’ll be answering a few common questions about pressure treated wood. What it is, whether paint is the best option for pressure treated wood and set out a helpful guide about how to prepare your pressure treated wood for painting and how to paint it so that it leaves a nice, smooth finish.
Let’s get started.
So, What Actually Is Pressure Treated Wood?
You may be unfamiliar with this term if you’re new to woodworking, or if you haven’t dealt with this type of wood before.
Pressure treated wood is a type of lumber that has undergone a special treatment process so that it can resist rot, decay and damage from bugs. It is submerged in a pressurized tank where the wood absorbs the chemical preservatives.
There are three main families of pressure treated lumber:
Borate
Alkaline Copper Quat (ACQ)
Other rot resistant treatments and non-combustible.
How Can I Check If My Wood Is Pressure Treated?
If you’re a novice to woodworking, all wood may look the same to you. You needn’t worry though, it can be difficult for some experts to determine if wood has been pressure treated. There’s a few easy steps to determine whether your wood has been pressure treated and we’ll outline them below.
Step 1: Look For An End Tag
There may be a stamp on the actual wood that tells you that the wood has been pressure treated, it should outline the preservation company and what preservatives have been used.
If your lumber’s end tag states that it has been treated with Chromated Copper Arsenate (CCA), you should take it back to where you bought it, or safely discard it.
Wood that has been treated with CCA has been banned for outdoor projects for a number of years since it has a form of arsenic in the preservatives.
Any other tag is absolutely fine, but it is essential to check in case your wood has been treated with CCA.
Step 2: Locate The Stamp
A stamp will tell you what type of wood it is and what it is good for. For example, a stamp marked with ‘FDN’ is one of the safest varieties of treated wood as it is designated for use as a floor foundation.
Additionally it will tell you what species of tree your wood has come from, for example, if it has come from a Southern Yellow Pine it will be marked with the letters ‘SYP’ or ‘SPIB’.
If you’re looking for a treated wood that can be used safely both internally and externally, then borate treated lumber is your best bet. It will protect your structure from bugs, fungus and anything else that is a threat to your wood.
Step 3: Check The Color
This step isn’t always the most helpful as most pressure treatments can come in all different colors, so it will be different for each type of wood. That being said, pressure-treated wood can come in tan, olive, brown or green.
So if your wood is a slightly different color to the species of tree it has come from, then odds are it has been pressure treated.
Step 5: Smell The Wood
If the above fails, then take a big sniff of your wood and if your wood smells like chemicals or oil then it’s most likely been pressure treated.
Hopefully after doing a few of these steps, you’ll know if your wood is either treated or untreated.
Is Painting Pressure Treated Wood The Best Option?
You may be wondering if painting the pressure treated wood is the right choice or whether it’s best to leave them as it is or consider staining.
Staining will penetrate the wood whilst painting will only cover the top layer.
Staining is regarded by some experts as better since it will protect and preserve the natural beauty of your wood and it’s also easier to change once you decide to use a new color, whereas with paint you’ll have to completely strip the paint on the top layer and risk destroying the top of the wood.
But, you can have most colors you want if you choose to paint and whilst stains do come in a variety of colors, it’s not as colorful as paint is.
Some people will advise against painting your pressure treated wood, and this is because the paint will not fully absorb into the wood which allows moisture to get stuck in the wood and thus create mold and mildew.
Whilst mold and mildew isn’t destructive to your wood, it can be dangerous for humans to breathe in. Paint can also be much harder than stain to apply and if you are planning to paint it, you’ll need to be very careful and ensure you take the right steps. Which we’ve outlined below.
Getting The Pressure Treated Wood Ready For Painting
Preparation is key before you embark on painting your wood. It can help ensure that your wood lasts longer and so that you won’t have to keep applying coats of paint more frequently.
Let The Wood Completely Dry
This is possibly the most important step in the whole process. Whilst you may be eager to paint your pressure treated wood straight away, If you’ve bought your wood from a store, it’s likely to be wet from the treatment process, most pressure treated woods will have to be left to dry for three to four months and maybe longer depending on the climate in which you live.
Do not overdry it either. This is a difficult step as there’s a small time frame between the wood being wet and overly dry. To minimize this happening, periodically check for the moisture content within the wood.
So How Do I Know When The Wood Is Dry Enough?
Naturally you should touch the wood to feel if it is dry, if it still feels wet then it needs more time to be dry. If you’re unsure if the wood is dry or not, you can perform a quick ‘sprinkle test’.
Sprinkle a few water droplets onto the surface of the wood, if the droplets start to bead up immediately then unfortunately your wood is still wet, if the wood absorbs the water then you’re ready to start the painting process.
If you’re in a hurry to speed up the construction of your project, you can help the wood dry faster by arranging the wood in a criss cross pattern and placing them in the sun so each side of the wood is able to air-dry.
Clean The Wood
It’s important to clean the wood prior to putting anything onto the wood. You should use a bristled brush and some soft detergent (or just soap and water) to remove any debris that has accumulated on the wood.
Unfortunately you’ll have to repeat the drying process which can take a few weeks and you can keep checking if the wood is dry by using the ‘sprinkle test’ we mentioned earlier. Alternatively you can press a nail into the wood, if any water comes out whilst you’re pressing it into the wood then it needs more drying time.
How To Paint Pressure Treated Wood
We’ll list what tools and products you’ll need here so that you can save time by buying these ahead of time, or you may have some of these just laying around your home.
What You’ll Need
Latex paint
Paintbrush
Soft detergent
Primer
A brush for cleaning the wood.
Once you’ve obtained these tools, now you’re ready to start painting your pressure treated wood.
Step 1: Use A High Quality Latex Primer
Using a primer before the first coat of paint lets the paint adhere a lot more easily to the wood, it also helps stop the wood from absorbing the top layer of paint, leaving a patchy mess.
Ensure that you’ve bought the correct primer, the best ones to use for outdoor use are primers labeled for exterior use, also try to avoid oil-based primers and paints if you can.
Use the brush to carefully paint the primer onto the wood’s surface, use long and straight strokes to ensure that the primer coat is applied evenly and thoroughly.
Step 2: Use A High Quality Exterior Latex Paint
Again, apply the paint using a paintbrush and use straight and long strokes so that the paint is applied evenly. You should apply two coats of the paint onto the wood, as the first coat of paint will usually flake off after about six months, the second coat will allow a longer lasting finish.
Try to ensure that you’re not painting in the direct sunlight, as the paint can dry up faster than you apply it. Also note that the curing process can take a day or so, but the first coat should not cure before you apply the second one.
If you can, avoid using oil-based paint as it won’t adhere to the wood as well as latex paint will, also try to ensure that you have got exterior paint as it will be more suited against the elements.
With anything you buy, always make sure to read the instructions of the paint or primer you have bought, every paint is different so we can only offer a generic set of instructions.
Step 3: Use A Water Repellent Finish
Using a water repellent finish will completely seal the wood entirely, as water can seep through the pores of the wood. There are a few ways to completely seal your wood from water:
Use tung oil or linseed to create an antique and protective finish.
Seal the wood using a coating of polyurethane or varnish
Use a stain-seal combo to protect your wood from water, damage and decay for years to come.
You can also add an ultraviolet stabilizer that will block the sun’s rays from penetrating the wood, which can damage the wood fibers and make them more prone to cracking or splintering, which can be really annoying especially if the wood is going to be walked over and will mean the wood won’t last as long.
But that’s everything and hopefully your new deck or fence is looking better than ever!
There are a few additional steps that are optional, but are concerned around ensuring that the wood you’ve used lasts as long as it can.
How To Maintain Your Newly Painted Wood
Maintaining your painted wood can ensure that the wood lasts for years to come. The most common concerns surrounding painted wood are UV protection, mildew growth and shrinking and swelling.
As we mentioned earlier, if you don’t waterproof your wood then it can be susceptible to mildew growth as it retains moisture within the wood.
To minimize this happening you should waterproof your wood using the methods we listed above and you should have adequate ventilation between each of the boards, so that water doesn’t get stuck between them.
If mildew and mold has already occurred then you should take these steps and also clean the wood using three parts water and one part bleach and then moisten a sponge and gently clean the mildew from the wood, avoid using too much water as this will repeat the process all over again.
Alternatively, you can use an exterior wood cleaner mixed with warm water and try this process.
To prevent mildew from reappearing you can spray on a wood-safe fungicide and then leave it to dry.
You should also have an ultraviolet stabilizer on your painted wood, this will stop the sun’s harmful rays from wreaking damage on your wood. You should apply this after the paint has completely dried or after cleaning your wood.
Shrinking and swelling will occur naturally due to the wood being in direct sunlight, as the wood dries out it will shrink.
This is why ensuring your wood is completely dry before installing it is recommended, applying a sealant or stabilizer can stop the drastic effects of shrinking, but it won’t completely eliminate them.
Using modified wood before the painting process such as kiln-dried or KDAT instead of regular pressure treated wood can be much better as it won’t shrink significantly and can last for years.
Swelling will occur when the wood is completely soaked in water, to try and minimize this, try to inspect your wood as often as you can. If there is any water on the wood, wipe the wood dry, then ensure there are no gaps that are vulnerable to moisture and if there are, use a waterproof sealant to seal the gaps every year.
Why Should I Use Pressure Treated Wood To Begin With?
You may be wondering what the advantages of using pressure treated wood are, since it is such a hassle to use and has lots of rules to take into consideration before starting the staining or painting process.
And you may be inclined to use regular wood so that you can immediately paint the wood and start the construction process.
Well there are many pros and cons to pressure treated wood. The first is that unlike regular wood, pressure treated wood is a lot more dependable. It is resistant to bugs, moisture and fungi and can even sometimes be fireproof.
It will also last a lot longer than regular wood due to the chemical preservation it goes through in the pressure treatment.
This wood is also a lot more affordable than say cedar or redwood. So if you don’t want to break the bank when constructing your project, the boring drying time of pressure treated wood is definitely worth it.
You may be wondering about the downsides of this type of wood, if any. Sadly there are a few. The painted wood will start to dry out in about six months and when it does you’ll be able to spot checking but this can be minimized by using a good wood sealer.
You’ll also be able to start spotting splinters on the wood over time due to the wood being in the direct sunlight, the extreme heat and humidity beating down on the wood will start to dry out the wood and cause the paint coat to fade (this is why two coats of paint is recommended!).
But if you don’t want to constantly be checking over your painted wood or worrying about it drying out, staining is recommended as the color will stay a lot longer and can be changed a lot more easily.
What If I Painted The Pressure Treated Wood Before It Was Completely Dry?
If you’ve accidentally painted the pressure treated wood before it was completely dry, this can sadly ruin your new deck or fence. It will cause the wood to warp as wood will shrink and swell when it is wet.
So if you’ve got some sides of the wood that are perfectly dry and others are still wet, this will cause the unpainted side to dry before the painted side which again results in warping due to excessive moisture content.
It will also cause the paint to not properly adhere to the surface of the wood, which will make it so you need to apply a lot more than two coats, and thus waste money on multiple paint cans.
So, if this has happened to you, you’ll most likely need to buy new wood and wait for the new wood to dry, which can take a few months.
Final Thoughts
After reading this guide we hope that you’ve been able to paint your newly bought pressure treated wood and now have a beautiful looking deck or whatever you have chosen to create.
You should now know how long it takes to dry out the pressure treated wood before painting it and what can happen if it isn’t dry enough when painted.
From reading how to maintain your painted pressure treated wood, hopefully you know how to ensure that your wood can live as long as it can, so that your project stays looking good even after a few years.
We’ve also added in a few FAQs in case you have any questions regarding anything mentioned in this article.
