How to Stain Pressure Treated Wood Deck – And When?

how to stain pressure treated wood deck

As the summer is coming up, more late-night chill sessions happen on patios and decks around the world.

However, building a deck can be a large endeavor on the surface, but in reality, if you follow some simple steps, you can get the patio of your dreams relatively cheaply and easily.

In this article, we will be investigating everything to deal with mostly staining and sealing pressure treated wood that you can use on your deck/patio.

Why Stain Pressure Treated Wood?

Most pressure treated lumber wood come with special markings (stamped) and an end tag that can help you know whether the wood is treated or not.

Many of these stamped markings on the lumber would also indicate whether the wood is rated for “ground contact” or “above ground use” only.

Smelling the wood for a unique oily smell (due to chemicals present) can also help you know if the wood is already treated.

No matter it’s treated or not, wood is susceptible to rotting especially when it is constantly bombarded by solar rays, moisture from rain and snow, or even wind.

However, lucky for us, staining treated wood can increase its lifespan to many-fold.

Not only stain adds extra protection against the previously mentioned hazards by added preservatives and chemicals but also it will give the wood a fresh new look.

Staining is especially important for wooden outdoor objects such as desks, picnic tables, wood fences, and of course your decking area.

In my opinion, anything that will be seen by anyone should be stained just so it looks better.

How to Stain Pressure Treated Wood Deck?

Remember – staining a new pressure treated wood too soon is not good unless it is completely dry and ready to stain.

When you see that the wood is ready you should start by choosing the right kind of stain that is designed for staining treated wood.

So, let’s jump into and the steps for how to stain wood deck.

Step 1: Gather Your Tools

To stain wood in general, you will only need a few tools. You will need a few scrub brushes and a few paint brushes.

You will need some safety equipment such as gloves when you work with the stain.

And of course, you will need a paint mixer (or paint stirrer sticks) and some paint can openers.

Finally, you will also need to have a pressure washer as it is important in this process.

For materials, it is pretty self-explanatory.

You will simply need wood stain and deck cleaner. The amount of course will be based on the size of the project.

You will have to look at the specific sealer and stain you are using to determine how much surface area you can cover.

Step 1: Choose the Deck Stain

There are tons of different types of stains that you can choose from.

However, we can give you some recommendations.

Two options you have to choose is a transparent or a semi-transparent stain.

  • A clear or transparent stain (like Thompsons Waterseal Transparent Waterproofing Stain) is a lot less strong and contains not a lot of pigmentation.
  • A semi-transparent (like DEFY Extreme) is probably the more common stain type that has a lot of stronger colors and pigments that are ideal for pressure-treated wood.

The other big option is the color of the stain.

There are dozens of various types, but we will split them into two options, lighter colors and darker colors.

And these colors are exactly what you think. Lighter colors are more yellow and bright while darker colors are browner and darker.

This is mostly your preference, but if you plan on keeping this wood for a long time, we suggest staining with a lighter color, as in the future you will be able to stain it again with a darker color.

Plus, if you know a little about light, you will know lighter colors will absorb less heat than darker colors, which is better for the long-term lifespan of the wood.

Step 2: Prepare the Wood

Before we stain, we have to make sure the wood is nice and clean.

Although this step may not be important if you have brand new wood, this is absolutely required if you are using wood that is old or dirty.

You may be able to get away with a quick wash with your hose, but we recommend doing a deep clean of the weathered wood.

To deep clean your wood, you will need a deck cleaner. Any old deck cleaner should do just fine, and you should be able to just follow the instructions on the can.

After a short waiting period, we will want to wash it off with a pressure washer to remove the cleaner and any stains that would be on the wood.

Before we stain, we will want the wood to be dry, so move it to a nice dry place where it can dry and wait about 24 hours.

Step 3: Prepare to Stain

Stain can be extremely tricky to work with, so make sure you read this section all the way through.

Before we even begin, we will need a place for it to dry, however it should not be in direct sunlight as the stain will dry too fast and it shouldn’t be inside a house due to the strong smells associated.

If this can’t be done, like on a wooden fence, you will be fine as long as you do it properly.

We will want to use tarps or painters’ tape to protect the environment near the wood that is about to be stained.

It may be even better moving as much as you can away. This is a really important step as wood stain will stain anything.

Cleaning any spilled or accidental stained things is extremely difficult, so if you can avoid it, that will be best.

We are almost ready to stain pressure treated wood on deck, but there are a couple minor steps.

You should brush the wood one more time with a brush to remove any dust or leaves that may have fallen on it overnight.

Quickly read through the wood stain’s instructions to make sure you know how to use it.

And finally, you should practice applying the stain using your preferred deck stain applicator on a piece of scrap wood to make sure you know how and are satisfied with the pigment.

Step 4: Start Staining

Finally, we can actually stain the wood! To stain, it is pretty simple, as it is similar to painting.

Just follow the instructions on your wood stain. You may be able to get away with a roller but we recommend using a paintbrush for most of it so you can get in cracks and crannies.

One coat is probably fine, but it totally depends on the project, the stain, and the wood itself.

Like we said, it is super similar to painting, so follow all of the guidelines you use when you paint. Like make sure you stain every part, even the ends.

And on vertical pieces of wood, make sure you start at the top and make your way down, working with gravity.

Before doing anything else with the wood, make sure you wait 24 hours for the stain to dry or whatever the stain recommends.

How to Seal Pressure Treated Wood

When Can You Stain Pressure Treated Wood?

This entire article has been talking about staining wood and hinting at staining pressure treated wood, however, there is a little secret we haven’t told you – which is about the right time to stain the wood.

For getting the best results its recommended that you stain your decking area when the temperature is between 50 and 90 degrees. Also, avoid staining in direct sunlight.

Before staining you would also need to make sure that your wooden deck is clean and dry.  

As you may know, pressure treated wood is simply wood that has chemicals in it to repel water and in general make it stronger.

However, in this process, the piece of wood gets incredibly wet, and to be frank, you can’t use stain on a wet piece of wood as it won’t stay on.

To fix this small little issue, we have a few options.

Picking a different type of wood is the easiest way. There are a few different types of pressure treated wood that has already been dried.

At the hardware store, look for “kiln-dried” wood, as the name implies, has been dried out already for you in a kiln.

If you have freshly pressure treated wood, you will have to dry it out yourself. Simply put it in an open space, preferably with a lot of air flow.

The time you will have to wait will vary from project to project but expect it to take a few days to a couple weeks.

To determine if the pressure treated wood is dry enough, we can use the sprinkle test.

As the name implies, all you do is sprinkle water on the wood. If the water is absorbed in the wood within ten minutes, it is ready to stain.

However, if the water just sits on top in a pool, you will have to wait more time for it to dry.

Whenever it is completely dry, you should be able to stain it effectively.

Do You Need to Seal Your Treated Wood Deck?

Some people may want to seal their wood they just stained because logically it makes sense.

However, I’m here to tell you that you probably don’t have to.

If you can tell on the wood stain you used, most stains actually have a sealant built in.

This sealant will protect your precious wood from moisture, the natural enemy of wood.

But more importantly, a sealant will tend to provide an extra layer of protection for the wood in case of scratches or other impacts.

Using a sealant on a stained piece of wood doesn’t combine the power of the two, but rather will result in an undesirable appearance.

However, if you didn’t stain your wood, you can and should apply sealant.

Deck sealers usually provides a clear and transparent coating to protect the wood.

It’s ideal for those who need to get the most natural wood look while also offering the best protection.

If you are working with pressure-treated wood, you will want to have a sealant that specifically is designed to be UV repellent.

This will avoid wood turning gray faster due to harmful UV rays.

You can apply a deck sealer very similar to paint or stain, just brush it on and that’s all you really have to do.

A little fact is that most outdoor projects such as decks actually are required by building codes to have pressure-treated wood as it is simply better at surviving weather conditions.

Do You Need to Stain the Underside of a Deck?

The short answer is no, it’s not essential.

The underside of the deck is naturally protected from the elements by the top side of the deck.

This is particularly true if the deck is constructed using pressure-treated wood that keeps the insects out.

However, there may be other reasons to stain the underside of the deck, especially if it can be seen or if there is a unique situation that might expose the underside to the elements.

Some of the benefits of staining and sealing underside deck are:

a) Visible:

If the deck is part of a balcony or second story that will be seen, you can have it stained for both aesthetic and practical reasons.

One layer of stain will provide good protection from the elements for the underside of the deck.

b) Prevent Mold & Mildew:

The biggest advantage to staining the underside of the deck is to prevent mold and mildew from sticking to the surface.

This is especially true if the climate is mostly hot and humid or the wood is exposed most of the year to moisture.

If leaves or other debris tends to collect under the deck, it may increase the humidity levels and provide a home for insects and fungi to start going after the wood itself.

You can clean out the underside of the deck regularly to prevent this from happening and a layer of stain will provide extra protection.

Steps for Staining Underside of a Deck

If you decide to stain, then you will need to clean the underside area properly.

Try a deck wash that uses a formulated cleaner designed to remove dirt, debris, and other contaminants while also getting rid of loose particles.

Plus, any fungi that has managed to take hold will be removed as well.

Step 1. Get Plenty of Stain

You’ll want to have enough stain to cover the entire underside, so be sure to mix the stain you purchase together.

This will let you know if you have enough and it will smooth out any color variations that may exist between the stains.

Step 2. Splash Test

To ensure the stain will stick, splash a little water on different areas of the wood.

If the water beads or the wood does not absorb the water in 15 minutes, then it will not take to the stain either.

Using a wood restorer or cleaner will help to open up the wood so that it accepts the stain.

Step 3. Apply the Stain

Now you are ready apply either a water-based or oil-based stain. If you want a shiny, deep finish, then oil-based is the way to go.

A water-based stain provides more of a flat finish, so choose the one that works best for your needs.

Apply the stain evenly across the underside of the deck and wait 24 hours for it to properly dry.

Once it has dried, you should check for any open spots to ensure that it is all covered.

After that, you should only need to check the underside of the deck annually to see if the coating is still present.

You may want to check more often if debris has built up on the underside.

what if it rains after staining deck

What to Do If It Rains After Staining Your Deck?

After you have successfully applied the stain, you have not won the war.

There are a few things you should consider before and after you stain your pressure treated wood.

As stain actually seeps into the wood and becomes part of the wood, it is super important for it to dry properly.

The biggest concern for most staining projects is the weather, as the rain could completely ruin a stain job.

Staining with good weather is the best thing you can do. We briefly mentioned it before, but stain loves a nice cool and dry place when it dries.

If it is too hot or wet, you will get some splotchy spots and it simply won’t look as good.

We recommend to stain on a day where there is a light overcast, but make sure there is no chance of any rain to come for at least two days.

The overcast will prevent direct sunlight from ruining the drying process.

And as we mentioned, if it rains, the stain will be completely ruined.

If an overcast day isn’t an option for you, you can wait for the sun to go behind your house or near the end of the day where the sun won’t be beating on the wood for a long amount of time.

The Results of Rain & Fixing Rain Damage

We mentioned a few times that rain, or water will ruin a stain, but how exactly does it work?

Well stain takes multiple hours to set and then up to two days to completely dry.

If water gets on the freshly stained pressure treated wood deck, the water will actually seep into the wood, like how the stain did.

But as there is only room for one of the two liquids, the stain will be pushed out on top, leaving different areas where there is too little stain in one part and too much stain in others.

In my opinion, the whole point of staining, is to get a nice look on top of wood and getting the wood wet in that stage completely ruins it.

There isn’t an easy way to fix the stain after it is ruined by rain.

In fact, the only way to completely fix it is to sand the stain off the wood and completely re-stain it after it dries of course.

If this isn’t too appealing to you, (I hate sanding!) you can try to add additional stain and try to blend away the blotches.

However, it won’t be perfect if you don’t do it correct the first time!

What to Do with Leftover Pressure Treated Wood?

For a completely weathered and old deck wood it is nearly impossible to get them stained for reuse.

If you anyhow do it, it may not last longer and is therefore not worth your time and investment.

Investing in a new lumber wood and rebuilding your decking is a good option in this case.

Fortunately, there are also a few things you can do with your leftover pressure treated wood rather than just leaving the scraps left over as wasted.

1- Recycle

Scraps of pressure-treated wood that is leftover are more or less reusable.

One of the greatest ways is therefore to use it for building other smaller structures inside or outside your home.

2- Free Give Away

If you find no use of your old leftover wood, you can always give them for free to someone who is in need or can use it better.

You can simply pile them outside in your yard and have a signpost written “Free Treated Wood.”

Within a few days, you will be surprised to see how many people are interested and actually willing to take them for free.  

3- Check for Available Land Fills

Since you cannot burn the pressure treated wood (due to the very toxic compounds it has), dumping them inside a landfill can be another good way to dispose them off safely.

For this you will need to get in contact with your local authorities.

They can help you know about the availability of any landfills near you where you can dump the toxic treated wood.

4- Ask Your Trash Service to Clear

Contacting your local trash service can be another good way to dispose of your pressure treated wood.

Although this is not their job, they might help you clear off your area if you have loads of unwanted pressure treated.

5- Sell the Leftover at a Price

Besides all these, selling the leftover at a cheaper price is also a great way for re purposing that old treated lumber wood.

You can find someone who is in need and can pay you some price for the wood.

This option can be especially beneficial if you have a huge amount of timber wood scraps that you want to dispose of.  

The Bottom Line

Staining is super important in most wood projects, especially ones where the end result will be outside.

While you can easily stain the pressure-treated wooden deck in a DIY way, the stain may not last long if you do not follow the right procedure.

Make sure you choose the best stain quality and complete the task with patience.  

If, however, your old deck is completely weathered it’s good to dispose of the wood safely and rebuild rather than staining.

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