Sanding a Deck

Diannehope/morgueFileSpring has sprung and with it, a whole new lineup of household chores. Even if you dread the infamous “honey-do” list, there’s a sweet side to it, though. Home maintenance in May paves the way to outdoor fun when summer comes (yippee!). With that worthy goal in mind, here’s our guide to sanding your deck.

When to Sand Your Deck

For best results, sand your deck every 1-2 years. QUICK TEST: Not sure if you need to sand this spring? Try this quick test. Sprinkle the deck surface with a little water. The liquid should bead; if it’s absorbed, that means now's the time to give your deck some TLC.

Why Sand Your Deck

Improved appearance. Sanding your deck will improve its appearance by removing stains and traces of old paint prior to refinishing.

Comfort and safety. Remove splinters, rough spots, and trip hazards to get your deck in shape for the season, especially when your household includes small children or people with mobility challenges.

Longer lifespan for your deck. Sanding and refinishing will get rid of mold and keep out moisture to help your deck last longer.

What are the Steps to Sanding a Deck?

  1. Decide whether to DIY. Plan on a couple of weekends for this time-consuming (but rewarding) task. If you’d rather spend your spare time relaxing, find a reliable local carpenter to take care of the sanding and refinishing process. 
  1. Check the weather forecast. The best time for sanding a deck is when you can expect several days without rain.

  2. Inspect the deck surface for protruding nails or screws. These should be countersunk 2 mm or more so that sanding your deck will go smoothly and your sandpaper won’t end up shredded.

  3. Make necessary repairs. Repair or replace any rotted wood, rusted metal components, loose fastenings, etc.

  4. Wash your deck. Scrub with a deck cleaning solution. Pressure wash if the deck is very soiled. Then allow to dry completely, for 24 hours or more.

  5. Choose the right sander. Although a floor sander is great for wood flooring – indoors – it's not an ideal choice for the rougher, more uneven surface of a deck. Instead, use a belt sander (for large expanses) or a finishing sander (for spot sanding, as well as for corners and edges).

  6. Choose the right sandpaper. This depends on the kind of wood your deck's built from (see “Types of Deck Wood” below). Only go up to 60/80 grit sandpaper maximum, since you want the surface to be smoother, but not so smooth that it interferes with absorption of your finish.

  7. Remove sanding dust. Clear off all dust from sanding before applying finish. Use a vacuum cleaner, followed by a tack cloth (a cleaning cloth which contains a light adhesive to trap small particles such as sanding dust).

  8. Apply finish coat(s). Heavy-duty stain or specially formulated deck-and-patio paint is recommended for the floor of your deck. The finish should be able to stand up to foot traffic, as well as outdoor furniture and grills being dragged back and forth. 

  9. Wait to use the deck. After staining your deck, wait a minimum of 4 hours before walking on it and 24-48 hours before putting your deck furniture in place (if the weather is clear and dry, otherwise give it more time). Post-paint, keep heavy furniture off it for a week.

Types of Deck Wood

Hardwood (lumber from deciduous trees, such as redwood) can handle sanding with 20-grit sandpaper if necessary to correct warpage. Follow the initial sanding with a finer grain to smooth the wood.

Softwood (lumber from coniferous trees, such as cedar) needs to be treated more gently. The first sanding should be done with 50-grit sandpaper.

Pressure-treated lumber. PT lumber has been treated with preservative chemicals and therefore must be handled with special care. It’s possible to sand pressure-treated lumber, but protect yourself with goggles, dust mask, and work gloves. After sanding, wash hands well before handling food.

Laura Firszt writes for

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