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How and When to Waterproof Your Deck

Steve Thompson
June 4, 2021

Deck waterproofing is worth it on several levels. First of all, the return on investment is 100 percent, according to the North American Deck and Railing Association. Since wooden decks come in direct contact with the environment, it's essential to protect them in ways that extend their durability. Here are five crucial tips on when to waterproof your deck.

1. Take the Water Test

One of the most basic ways to know when to waterproof your deck is to apply a simple water test. Pour some water droplets on the deck, then check to see if they soak into the wood. If so, it's time for a new coat of sealant. Most wooden decks need to be resealed once per year, but it also depends on the amount of their usage and exposure to sunlight. So the water test is a more reliable indicator than the calendar on when to reseal the deck.

2. Plan Your Budget

One of the most critical factors to any renovation decision is whether or not it fits your immediate budget. It's possible, though, to apply frugal landscaping ideas that don't create holes in your long-term planning. The cost of sealing a wooden deck mainly depends on the size, type of wood, prep, and amount of labor required. Since it's something to plan for regularly, you should consider setting aside money each month for it.

3. Before or After the Rainy Season

Knowing when to waterproof your deck is essential because every region has its seasonal characteristics. The key is to waterproof your deck at a time when no rain is expected. Temperature is another factor that affects sealant. The ideal temperature for the sealant to dry evenly is under 85 degrees Fahrenheit. After the sealant is applied, it needs about three days to dry. Including preparation time, the total project may take up to five days in which there should not be any exposure to rain or moisture.

4. Consider Age of the Wood

Another critical indicator as to when you should waterproof your deck is the age of the wood. Brand new lumber maintains enough moisture that it can't yet absorb the sealant. It may take three months to a year before new wood is completely dry. Continued moisture is not good for your wood since it can lead to unhealthy mold and mildew. If you have a deck that's several years old, sealing it every 12 to 18 months should be an adequate time frame.

5. Prepare for Waterproofing

Once you decide your deck needs waterproofing, it helps to make preparations for the process. The first step is to clean the deck with a hose and scrub brush thoroughly. Then use sandpaper to smooth out rough areas where splintering or defects exist. You may also need to fill in holes with wood putty.

Be aware that wood fillers often come in tubes and harden quickly once exposed to air. At this point, you should replace any boards that have begun to rot. Once you've reached this point, your deck is ready for the waterproof sealant to be applied. Remember that the deck needs to dry for at least 72 hours before someone can walk on it.


Understanding when it's the right time to waterproof your deck is part of the secret to a long lifespan. These tips will help you overcome nuances with your deck. Remember that a wooden deck can last a long time if you give it the proper care.