What to Know About Sealing a Deck

Consider this your comprehensive guide to sealing your wooden deck so it lasts for years to come.

It may not be at the top of your summer to-do list, but deck sealing is a chore you don't want to skip. We've all seen one—a gray, weathered deck with an aged look that channels the opposite energy of the lively and fun feel you want from an outdoor (and properly sealed) deck. Sure, there's a place for that weathered wood look, but a sun-scorched deck can drastically reduce your home's curb appeal. Plus, this visual indicates a deeper issue at hand, as a neglected deck is more likely to fail prematurely, leaving you with major expenses and potentially putting your family, guests, and pets in danger.

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Avoid the unsightly appearance and great risk that comes with a weathered deck by keeping your deck properly sealed. While deck sealing requires a little elbow grease, it's surprisingly simple to complete yourself. Plus, once you see the glisten and glow of a properly sealed wood deck, all that work will be more than worth it. Read on to learn everything you need to know about deck sealing, from how to seal a deck to which types of stains and sealants to use and when the ideal time to get the job done is.

What Does Deck Sealing Mean?

As the word sealing gets tossed around rather loosely in the DIY and home improvement world, it's important that we definitively explain what it means to seal a deck. Most wooden decks are constructed using softwood, such as pine. Because pine is readily available and much more affordable than hardwood, it's perfect for this sort of construction. But because of pine's soft nature, it's much less durable than hardwood and its moisture and UV resistance is less than ideal. To compensate for this, wood decks are sealed with different types of deck sealants. While the sealants are not permanent and have to be reapplied, they offer protection to the wood and protect against rot.

Staining vs. Sealing

Though often combined and confused, there are major differences between stain and sealant. The major visual difference is the presence of pigment. Sealant will sometimes have pigment that will color the wood when applied, but stain will always have pigment. Additionally, the levels of protection vary between the two products. Stain offers little to no moisture protection, while sealant offers tremendous moisture protection. Conversely, clear sealants offer little to no UV resistance, while the pigment in many stains can act as a UV barrier for the wood.

To protect your deck from both moisture and sun damage, you need to first stain it, then follow that with a clear sealant. You can now find modern products that combine stain and sealant to make complete deck protection a one-step application process, after the necessary prep work. Look for staining sealants that specify both UV and moisture protection, then reference the manufacturer's instructions for application.

How Much Deck Sealing Costs

The average cost of getting your deck sealed by a professional is around $900, though your actual cost will vary by your location, the size and condition of your deck, and other factors. Since tackling this job yourself will save you anywhere from 50% to 75% of the overall cost, according to HomeAdvisor.com, sealing your deck is a relatively affordable way to increase your home's curb appeal and protect your investment in a deck. The cost of materials will be determined by the size of your deck and the quality of the materials you choose to use. We recommend skipping the bargain deck sealants and opting for something of higher quality, as these products will typically offer better and longer-lasting protection.

How Long Deck Sealing Takes

Like the cost, the amount of time it takes to seal a deck depends mostly on the sealant you choose. When shopping for deck sealants, pay close attention to the manufacturer's instructions for application. Some sealants require the deck to dry for at least 48 hours after cleaning, while others can be applied directly to a wet deck. It's important to familiarize yourself with the product to understand the time commitment. Nearly all sealants will require a period of dry weather following application, so be sure to check the forecast before starting. During the drying time, make sure no people (or pets) step foot on the deck.

If your deck is in poor condition and needs substantial repairs or cleaning before it can be sealed, the length of time this project takes will be much longer, as you want your deck to be in good condition before you seal it.

How to Seal a Deck

The first step to sealing a deck is washing it. The quickest way to remove that dull, weathered layer from your deck, along with any grime, is to pressure-wash the surface. Use a fan tip and consult the pressure washer's manual for instructions regarding the distance the wand should be held from the surface. This will help prevent gouges in the wood.

Once the deck has dried, take a walk around the deck and look for any broken or loose boards in need of repair. Replace broken boards and screw loose boards tightly in place. This is also a good time to address any squeaky boards, or other complaints you've had with your deck or even sand your deck, if desired.

Next, apply your staining sealant according to the manufacturer's instructions. Be sure to cover all edges and joints to ensure the sealant penetrates the entire surface. Let the deck dry for at least 48 hours before walking on it.

Pro Tip: For best results, consult the temperature and humidity guides on your deck sealant and plan accordingly to ensure you get the best possible outcome.

Deck Sealing Tips and Tricks

There are a few simple ways you can take your deck sealing to the next level.

Sand the deck. While this step is optional, sanding your deck with a pole sander will improve the look of the wood and encourage deeper penetration of the sealant. A quick pass before sealing using 120-grit sandpaper is all it requires. Once finished, use a leaf blower to remove all dust and debris.

Deep clean the deck. To further clean and brighten the wood after pressure washing, apply an all-in-one deck cleaner to the deck's surface. While you should consult your specific cleaner for application, most cleaners are best applied using a pump sprayer. Consult the manufacturer's instructions for dilution requirements and safety practices. Wash away the cleaner with a garden hose, then allow the deck to fully dry for 48 hours or the time specified on the cleaner.

Remove tough stains. Even after pressure washing and applying deck cleaner, tough stains can remain. To remove these, use nonchlorine bleach. Simply apply the bleach, scrub with a stiff brush, and wash away with water.

Reseal on time. Even the best deck sealants aren't permanent. After sealing your deck, read the instructions for resealing and jot when it needs to happen down on your calendar. Keeping up with resealing is the best way to protect your deck.

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