How to Stain Pressure Treated Decks

Beth Asaff
Pressure Treated Wood Deck

Learning how to stain pressure treated decks can help you keep your deck looking great, while saving you hundreds in professional labor.

Pressure Treated Wood

Most decks today are built of pressure treated lumber made of pine, cedar or redwood. Pressure treated wood is made by infusing chemical preservatives deep into the wood. These chemicals help protect the wood from insects and fungus and treatment lasts up to 20 years, greatly extending the life of your deck.

While this treatment does help to protect your deck and extend its life, you still need to seal the wood to help protect it from weather. Sun, rain, snow and mildew are all factors that can age a deck in just a few years, so learning how to stain pressure treated decks can help preserve their lifespan.

Choosing a Deck Stain

If your deck is brand new, or was built after 2004, you have your choice of deck stains, sealers, colors and treatments. Choose from opaque stains, which mimic the look of paint, semi-transparent stains which give a hint of color to the deck while preserving the appearance of the wood grain, and clear sealers which preserve the appearance of the wood, but need to be reapplied frequently. Be sure to avoid paint however, since pressure treated wood doesn't accept and bond to paint the way untreated wood does.

If your deck was built prior to 2004, the best deck treatment is a semi-transparent stain. This is because prior to 2004, pressure treated woods frequently contained arsenic to help repel insects. Unfortunately, this chemical has been found to leach out of the wood into the ground surrounding the deck, or to peel up with paints or opaque stains. A semi-transparent stain will seal in the arsenic however, while keeping the deck looking great.

Staining a Pressure Treated Deck

Whether your deck is brand new or several years old, you can seal, stain and treat your deck yourself to help protect it and keep it looking great.

Instructions for Sealing Your Deck

  1. Allow new, pressure treated wood to weather for 30 days before sealing.
  2. Remove the old stain, along with any mold or mildew from an old deck by using a pressure washer and deck cleaning solution. Set the pressure washer between 1500 and 2500 PSI to avoid damaging the deck, while still removing old stains and debris.
  3. Allow the wood to dry thoroughly for 3 - 5 days.
  4. Use a roller or paint brush to apply the new stain in an even coat. Remember to seal the ends of the boards as well, since moisture can enter at these points.
  5. Apply one coat of color-based sealer and a second coat after one year.
  6. Apply two coats of clear sealer, with a third coat after 6 - 8 months.

Tips and Considerations

When sealing your pressure treated deck yourself, remember to keep a few things in mind to achieve the best job possible.

  • Use a mixture of bleach and water to kill mold and mildew on the deck.
  • Use light colored stains in direct sunlight to avoid having the deck become too hot.
  • Do not use oil based stains in shady areas, as this will encourage the growth of mildew.
  • Use a tarp below the deck to catch dripping stains or sealers onto the pad below.

By treating and sealing your pressure treated deck, you are prolonging its life and saving hundreds of dollars in repairs and professional treatment. Learn how to seal pressure treated decks today and enjoy their use for years to come.

How to Stain Pressure Treated Decks