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How Much Does It Cost To Seal Or Waterproof A Deck?

Typical Range: $551 - $1,277

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September 20, 2021

Reviewed by Robert Tschudi, Home Building & Remodeling Expert.
Written by HomeAdvisor.

Cost to Seal a Deck

Sealing a deck costs $894 or typically between $551 and $1,277. You’ll pay $0.75 to $4 per square foot for both materials and labor. Labor alone makes up 50% to 75% of the total price. Cost factors include regional worker rates, complexity, size, prep needs and accessibility.

A regular upkeep schedule will do wonders for keeping it looking new, preventing fading, and keeping the wood from splintering. Seal your wooden patio every few years to keep it beautiful. Humid climates or those with heavy rainfall might need it every year. Staining and sealing your deck helps preserve it against the elements.

“Regular deck maintenance will keep the deck safe and up to date,” says Bob Tschudi, Angi Expert Review Board member and Raleigh, NC-based general contractor. “Without regular maintenance most decks will quickly deteriorate.”

On This Page:

  1. Deck Cleaning and Sealing Cost Calculator
  2. Deck Sealing Cost
    1. Labor Costs
    2. Sealant Prices
    3. Sealing and Staining
  3. Cleaning and Refinishing Costs
  4. Penetrants vs. Sealers
  5. DIY or Hire a Pro
  6. FAQs

Deck Cleaning and Sealing Cost Calculator

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National Average $894
Typical Range $551 - $1,277
Low End - High End $250 - $2,100

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Cost data is based on actual project costs as reported by 8,211 HomeAdvisor members in .

Deck Sealing Cost

Deck sealing costs $0.75 to $4 per square foot, depending on your location, the amount of prep and cleaning necessary, and how complex the job is. Most projects cost $300 to $1,300.

Always clean before applying a sealant or stain. Use a good deck-specific cleaner and power washer set on low or use a brush and hose. Then, do any sanding and replace or repair any boards before sealing. Most pros include prep work in their price. Deck repairs cost $750 to $2,800.

Deck Sealing or Waterproofing Labor Costs

The labor to seal and waterproof your deck costs $0.50 to $3 per square foot but can go to between $2.50 and $7 per square foot if you have multiple levels, spindles/balusters, stairs and other features. Even with average labor costs of about $40 per hour, a 250-square-foot patio costs $125 to $750 in labor alone.

For some people, it’s worth hiring a professional to make sure it’s done right. Most of the price of the project comes from labor, which varies regionally. Also expect hard to access projects, like two story units, to take more time.

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Deck Sealant Prices

Most projects need two gallons of sealant which typically costs $50 to $80 total, but it can vary a little. in general the lower-priced options are often the thinnest and least durable. Here are some of the more common brands that both contractors and consumers use:

  • TWP (Total Wood protection): $30–$60 per gallon. Offers a full line of stains, cleaners, sealers, strippers and brighteners.
  • Behr: $35–$45 per gallon. A leading brand of stains, sealers, strippers, cleaners and finishes.
  • Thompson’s WaterSeal: $10–$40 per gallon. One of the most recognizable names in waterproofing and other exterior wood care.
  • DEFY Wood Stain: $40–$55 per gallon. Offers a line of stains and cleaners designed for durability.
  • Sherwin-Williams: $20–$50 per gallon. Claims of durability have held up under numerous reviews, and one coat usually does it.
  • Olympic: $15–$45 per gallon. Offers stains, cleaners and resurfacers. There’s a product for every budget, making it popular with DIYers and contractors alike.

Deck Sealing and Staining

Applying both a sealer and stain together costs $700 to $1,000 total. You’ll pay $300 to $400 for the sealer and another $400 to $600 for the stain. You’ll see this often on two tone projects. Sealing protects the wood from moisture, which can lead to mildew and mold buildup. Stains change a wood’s original color and provide a protective barrier, much like paint.

DIY Deck Waterproofing and Sealant Costs

If you decide to restore your deck yourself, you’ll spend $100 to $200 on supplies. The sealers cost between $20 to $60 per gallon. Waterproofing costs between $10 to $20 per gallon. Add tools (buckets, brushes, rollers, etc.), for another $20 to $40.

Remember that sealers will require multiple coatings, so you’ll probably need at least two gallons for most projects. A gallon only covers so many square feet:

  • One gallon of sealer covers 200–300 sq. ft.
  • One gallon of waterproofing covers 100–200 sq. ft.

Deck Sealing Cost Factors

Deck refinishing costs $600 to $1,400. It includes cleaning, sanding and making it look like new. Cleaning it costs far less, depending on which option you use, as listed below.

“Deck sealing is very important, even with new construction,” Tschudi says. “Not only does it protect the wood, the sealing enhances the appearance of the deck, which buyers appreciate.”

  • Power or pressure washing a deck costs $250–$400 on average. But be careful, it’s easy to damage wood with too much pressure. Note that while both power and pressure washing use high pressure water, a power washer also heats the water. If you are using a power washer, be sure to keep the spray away from nearby plants and foliage.
  • Sandblasting costs $2 per sq. ft. or $40–$65 per hour or around $860 total. Either option removes old stains, sealers and strips the top of any grease, dirt or oil.
  • Deck sanding costs $200–$350 on average. Sand for damaged, scratched, or heavily stained wood. It removes the top layer of wood.

Penetrants vs. Sealers

Penetrants soak into the wood’s surface while coatings sit on top of the wood. A coating sealer does both, whether it is 10% coating with 90% penetrant or a full 100% coating. Strip coatings before applying a new sealer. You can stain or seal over penetrants with a good cleaning. If you decide to apply sealers in place of or addition to stains, you can choose from a couple types:

  • Oil-based: A coating and penetrant. Harder to clean up and a little messier, but penetrates the wood and lasts longer.
  • Water-based: Coating only. They clean up easily with soap and water, making them attractive to the DIYer, but less resistant to wear .
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DIY or Hire a Deck Sealing Professional?

It’s worth it to seal or stain your deck, whether you do it yourself or have a pro come in. It’s an easy DIY project that just requires dedicating the time to do it properly. Many DIYers don’t do enough prep work which means the new seal fails early. If you don’t have the time, or need it to look professional the first time, find a local deck painting or staining service.

FAQs

Should I clean my deck before sealing it?

You should absolutely clean your deck first. Cleaning before refinishing it is critical. If you don’t remove dirt and debris, you’ll be locking these moisture-trapping elements into your wood. This will keep any new sealer from doing its job and lead to failure and costly repairs. Whether you need to sand, power wash or sandblast depends on its condition.

Is it better to seal or stain a deck?

Whether you seal or stain depends on many factors, including the type of wood, your climate, its age and how damaged it is.

How much does it cost to power wash and seal a deck?

Power washing and sealing a deck costs $500 to $1,700, depending on size.

Do decks need to be sealed?

Decks don’t need to be sealed, but if you want it to last, you’ll seal it with either a waterproofer, paint or stain.

How often do decks need to be sealed?

You should seal your deck every 1 to 3 years, depending on your climate.

Can I leave my deck untreated?

You can leave a deck untreated, but it’ll rot quickly and you’ll soon be replacing it. Deck replacement costs $4,000 to $11,500.

What is the best wood deck sealer?

It’s impossible to say which brand makes the best deck sealer. Most of them have similar formulations and pros vary on which ones they trust. Ask your professional to recommend one.

Still Have Questions About Deck Sealing?
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