how to seal a deck

When you want to relax, there’s nothing like sitting outside on your deck and enjoying the beautiful North Carolina weather. An outdoor deck provides extra living space and a great area to entertain, so it’s only natural that you would want to keep it in the best shape possible. Sealing your deck is one way to do this.

Sealing your deck is not a difficult DIY home improvement project if you know how to seal a deck. With the right tools and products, you can extend the lifespan of your deck and keep it looking new, longer. 

We’re going to share some tips to follow for how to seal a deck and why it’s so important.

Why is it Important to Seal a Deck?

You may think that since your deck is built with treated wood, sealing it is not necessary. But, treated wood does not last long in most weather conditions. The sun’s harmful UV rays will start to dry out the wood. When this happens, it is more vulnerable to rot and fungus growth.

Heavy rain and snowfall can also wreak havoc on your new deck when it’s not sealed. Adding a wood sealing creates a waterproof seal, preventing moisture from seeping in. It will also reflect UV rays and nourishes the wood. This prevents fading and keeps your deck looking newer for longer.

How to Seal a Deck

When it comes to how to seal a deck, there are three steps: 

  • Cleaning the deck 
  • Choosing a sealant
  • Applying the sealant to your deck

Clean Your Deck

Look for any dirt and debris between the boards on your deck. Use a putty knife or a screwdriver to loosen anything that may be lodged. Then, sweep away any debris so you have a clean slate.

You’ll then want to use a deck cleaner to make sure the wood is clean before you apply the sealant. If you notice any mold or mildew stains on a cedar or redwood deck, use a deck brightener to help remove these stains before sealing your deck.

Choose a cloudy day to apply the deck cleaner. This will prevent the sun from drying it out too fast. You’ll also want to protect any nearby plants or shrubs with a plastic sheet before you start.

Use a paint roller, garden sprayer, or a bristle brush to apply the deck cleaner. Always work from the bottom up when cleaning wood railings and posts. Working from the top down can lead to spills and spots that are hard to remove.

Follow the directions on the deck cleaner so that you apply it correctly and remember to rinse thoroughly. You’ll want to wait at least 48 hours before applying a deck sealer.

Choosing a Deck Sealer

Not all deck sealers are made equal. The more opaque the sealer, the better it is at fighting the elements. If you choose a lighter finish, more of the wood’s natural grain will shine through. The clearer the deck sealant, the more often you’ll have to clean and seal it, so always keep that in mind.

At Capitol City Lumber, we offer TWP 100 Series Deck Wood Sealer. This pre-mixed deck sealer is an excellent choice and available in 8 popular colors. It also resists splitting, warping, and cracking.

Applying a Deck Sealer

Once you’ve chosen your deck sealant, check the weather for two clear days when the temperatures will be between 50 and 60 degrees. This is optimal weather for this DIY home improvement project.

  • Sand the deck to remove any grain that was raised from washing it. 
  • Thoroughly sweep or vacuum when you’re done. 
  • Check for any nail heads or popped screws and fix those before applying the sealant.
  • Use painter’s tape on any siding, or any other areas you want to protect. 
  • Using a natural bristol brush, begin to apply the sealant, being sure the sealer gets into the joints where any two boards come together. You can also choose to use a paint roller if you have a larger area to cover.
  • Apply the sealer to three or four boards at the same time.
  • Be careful not to spill or overlap onto adjacent boards, this will lead to splotches that are hard to hide.
  • Let the deck dry for at least 24 hours before walking on it.

When you’re sealing your deck you may be tempted to go over it a second time with another coat. But, you only need one coat of sealant. That will do the trick and provide you with enough protection until it’s time to seal your deck again.

FAQ About How to Seal a Deck

When is the right time to seal my deck?

If your deck is brand new, you might not need to seal it right away. Freshly processed pressure-treated wood won’t be able to absorb the sealant well, so it won’t be that effective. 
To see if it is the right time to seal your deck, pour a small amount of water on the wood. If it absorbs quickly, it’s time to add a sealant. But, if the water pools and sits on top of the wood, you’ll want to wait a few more days.

How often should I seal my deck?

It’s generally recommended to seal your deck every year or two. Extremely hot summers or harsh winters can cause the sealant to wear away. Wear and tear from outdoor furniture and people walking on your deck will also make you want to keep up on your deck sealing.

Why Does Pressure Treated Lumber Need to be Sealed?

While pressure-treated wood has a chemical to keep pests away and protect from some moisture and rot, it’s not enough to keep it in great shape. A sealant offers the best protection against excess moisture.

What’s the Difference Between Staining and Sealing?

Some people think that deck stains and sealants are the same, but they are two different products. Sealants create a layer on top of the wood while stains penetrate the grain. While sealants and stains can change the color of the wood, a sealant works like a coat of paint by adding a pigmented layer. A stain uses pigments that are absorbed into the wood to change the wood’s color.

Stains do not offer as much protection as sealants and should only be used for cosmetic purposes. If you want to use both products, it’s generally recommended to stain the wood first and then apply a sealant.

Are you Preparing for a DIY Home Improvement Project?

If you’re preparing for a DIY improvement project that involves wood products, Capitol City Lumber is here to help. We offer lumber, wood siding, hardwoods, wood panels, hardware, and more. We are your one-stop for all of your project needs. Call us today at 919.832.6492 or reach out to us online to learn more about our products and how we can help with your next DIY home improvement project.