How Much Does it Cost to Waterproof a Deck?

As you’ve heard many times from us, the greatest danger to the wood in your deck is water. Over time, it eats away at the fiber, can lead to insidious dry rot or wet rot, and creates mildew. Wet wood is not only unattractive but dangerous to your structure.

Trex Protect deck tape is a great way to protect the tops of deck joists from early deterioration and rot.

A deck can begin to rot in as little as 8 to 10 years, so it’s vital to waterproof from the start. That’s why we always advise covering the tops of your joists and beams with flashing tape. However, if you have wood decking, you’ll also need to seal and stain your deck every two to three years.      

You probably spent a lot of time on deck costs during construction. Deck prices are important, but it’s also essential to remember the average price of maintenance in calculating the total cost.

So, how much does a waterproof deck cost? Let’s take a look at this cost guide:

Deck Waterproofing Cost Breakdown

The primary financial considerations for sealing or staining a deck are labor costs and product pricing. If you’re doing the work yourself, keep in mind that the average time to stain a deck is about 4 hours over the course of 2 days. However, if you have time, you can save significantly on the cost of paying someone to do this work.

Next, you must factor in the product: One gallon of stain covers about 200 to 300 square feet. The average deck is usually 300-400 square feet, so you’ll likely need two gallons, plus the rollers and brushes.

While it’s good to know the average cost, get more specific with a zip code calculator or a deck stain cost calculator from Homewyse. Further, home.costhelper.com provides the following guidelines:

• Hiring a handyman, contractor, or deck company to clean and seal a deck average about $2-$3.50 sq. ft. ($300-$525 for a 10’x15′ deck or $640-$1,120 for 16’x20′), depending on local rates, deck condition, the height and location of the deck, and the number of levels, railing, stairs, and other components.
• For a DIY seal or stain, supplies can cost $20 to $300 or more, depending on the cleaner and sealer used and any needed equipment. Renting a power washer can cost $40-$75 a day. DIYNetwork.com estimates that cleaning and sealing a deck is a relatively easy DIY project that takes about two days and costs between $100 and $250. Learn more about staining a deck from Home Depot.

Keep in mind that you may face additional decking costs if it needs to be repaired, such as replacing deck boards or sanding.  

Factors Influencing the Cost

Estimating the cost of waterproofing a deck isn’t straightforward because every deck is different, and the cost of labor can vary widely by geography. To make a more accurate estimate, you must consider the following factors:

• Labor cost. Look at the going rate for construction professionals in your area.
• Size of deck. The square footage of the deck will impact both time and material costs.
• Products. Look at the available sealants and stains available. Of course, some higher quality products will cost more; however, the cost may be worth it if they last longer.
• Cleaning.  Clean your deck before sealing or deck staining, and consider whether this is something you can do or whether you need to hire a service.  
• Quality. As with any other construction or home project, the best professionals will come at a great cost. It may be cheap to enlist a couple of friends to help you in exchange for pizza and beer, but will you be happy with the end result?

Waterproofing Options

When you consider waterproofing, be sure to remember a few vital details:

1. Remove all furniture and grills from the deck surface — do this yourself or include it in the price of your professional.
2. Allow up to 48 hours for the sealant to dry. Often you’ll need two deck coatings, and you need to allow two to three hours of drying between coats.
3. Choose a day that is warm and sunny if possible.  
4. An under-deck drainage system can also help waterproof your substructure. Learn more in this FAQ.
5. If you have special features, such as a pergola or benches, include time and product to stain them at the same time as the deck.

Smart homeowners take care of their decks. With a little waterproofing, your deck will last longer. If you’re done with sealing and staining, consider composite decking. Please make the most of our outdoor living space!