BestReviews is reader-supported and may earn an affiliate commission. Details
Expert Shopper Home

Early fall is the best time to seal your deck. Here's everything you need to know before you begin

Adobe Stock

Applying wood sealer to your deck this fall

Maybe you’ve been putting this home repair off all summer, or perhaps your deck is just starting to show serious signs of age. Either way, fall is an excellent time to seal your deck. Applying sealer helps protect the wood from water damage and keeps your deck from looking worn out.

Summer and winter are harsh on decks, and dry weather is the best time to seal — which makes fall the ideal season to get to work. Cool temperatures help the sealer sink into the wood before it can evaporate, and dry weather allows the sealer to dry quickly.

This article recommends the best wood deck sealer — an effective wood stain and sealer combination — as well as other tools and accessories you need to get the job done.

In this article: 3M Paint Project Performance RespiratorScotch Exterior Surface Painter’s Tape and Wen Corded Belt Sander.

How to know it’s time to seal your deck

Before you start, be sure your deck actually needs to be sealed. Sealing a deck prevents moisture from absorbing into exterior wood, which speeds up aging and rot.

Old decks: While obvious signs of wear or warping usually mean it’s time to seal, the droplet test is a simple and reliable method. After a few dry days, flick some droplets of water onto the deck. If they bead and sit on the surface, don’t seal your deck. If they absorb into the wood, the old sealant is no longer doing its job.

Recently built decks: If you just built a new deck or replaced most of the wood, you will likely have to wait before you can seal. This is because wood needs time to dry out, especially pressure-treated wood — otherwise you’ll just be trapping moisture inside. Most of the time, waiting a month is enough, but you can let your wood dry for a season to be safe.

Tools you need to seal a deck

Before you seal, make sure you have all of the tools you will need for each step.

  • Mask: A dust mask keeps you safe from fumes, chemicals and particles.
  • Sandpaper or sanderSanding down the aged surface not only smooths your deck but also helps it seal properly.
  • Pressure washerInstead of sanding, you can make quick work of the job with a pressure washer.
  • Bucket and spongeThoroughly cleaning the wood allows the sealant to stick properly.
  • Brushes and rollersA roller covers a lot of surface area quickly, while a brush helps you reach corners and other tight spots. Don’t forget the paint trays.
  • Stain: Without stain, the color of the wood will fade quickly. 
  • Sealant: Also called “seal” or “sealer,” this is the last step.

Sealing steps and common mistakes

Once you have your tools and gear, you can start staining. But as you can probably guess, you need to prepare your deck first.

  1. Pick a mild, dry day when it hasn’t rained recently.
  2. Sand or pressure wash your deck to smooth the surface.
  3. Remove all dirt and debris.
  4. After making sure the deck is completely dry, apply stain.
  5. Finally, seal the deck. Start from the edges and work inward.
  6. Add another layer of seal, paying close attention to difficult-to-reach areas and edges.

If possible, don’t stain or seal a wooden deck while it is in direct sunlight. Be sure to apply painter’s tape to any siding or railings that come into contact with the deck. When you’re done, give the deck a few days to dry completely to prevent damaging your hard work.

Best deck sealer and tools for the job

Behr Semitransparent Waterproofing Stain and Sealer

This is one of the best deck sealer and stain options available,  saving you a step and offering years of water and UV protection. The wood stain with sealer can be applied to fences and siding as well, you can use whatever’s leftover on other jobs.

3M Paint Project Performance Respirator

With replaceable cartridges, this respirator mask will last for years. Its comfortable design allows you to wear it for hours and breathe easily.

Scotch Exterior Surface Painter’s Tape

Designed specifically for outdoor surfaces, this painter's tape can be left on for days. If you have a larger deck that will take a few days to work on, this tape will resist weather well.

Wen Corded Belt Sander

The 80-grit sandpaper is gentle enough to smooth your deck but not coarse enough to cause damage. With an included dust bag, you don’t need to worry about creating more of a mess when it comes time to clean your deck.

Fly Hawk Paint Roller

Our pick for the best paint roller brush is extendable with a 4- to 8-foot range that keeps you off your hands and knees. The simple assembly and compact storage are well-suited to small spaces, and the 9-inch disposable rollers cover a large area quickly.

Bates Paint Brushes Four-pack

These are the best paint brushes for detailed work, available in a four-pack that includes a few sizes to reach tricky areas. Despite the low price, the brushes are durable and easy to clean.

Want to shop the best products at the best prices? Check out Daily Deals from BestReviews. 

Sign up here to receive the BestReviews weekly newsletter for useful advice on new products and noteworthy deals. 

Peter McPherson writes for BestReviews. BestReviews has helped millions of consumers simplify their purchasing decisions, saving them time and money.

BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers.

Share this post: