How to Maintain and Clean Pressure-Treated Wood

Floating decks (image) are an alternative for DIYers who want to build but lack the skills.
David Beaulieu

It’s likely that any wood-based outdoor project that you have installed is made of a popular wood called pressure-treated wood (or, at least, any outdoor wood project you install should be made of pressure-treated wood). Pressure-treated wood is best used on outdoor fixtures like decks, fences, beds, swing sets, pergolas, and arbors. This product is in high demand for most homeowners due to its lifespan, ease of maintenance, and durability.

What Is Pressure-Treated Wood?

Pressure-treated wood is wood that has been chemically treated to beat the weather elements as well as prevent mold from growing and rotting your wood. Some homeowners are worried about the chemicals that are used, but you can rest assured that the chemicals used are not harmful to anyone or anything, in small amounts. You can always get the extra protection by using gloves when handling the wood and wearing breathing masks and safety glasses when cutting pressure-treated wood. 

Because of this special chemical treatment, your outdoor fixture will last you and your family decades of fun. Most decks made with normal wood only last 10 years, while a pressure-treated deck can last up to 40 years! It’s easy to clean and stands strong against common wear and tear and bad weather.

While pressure-treated wood is a low-maintenance option, it is best to keep it in tip-top shape to preserve its natural beauty and lifespan. Cleaning and maintaining your pressure-treated wood project should be an annual chore that you perform shortly after the winter months. This will ensure that your deck is ready for year-round fun.

Depending on your pressure-treated wood fixture size, you should expect to put at least four to six hours (possible a day or two depending on rain or wet boards) of time aside to accomplish this task.

What You'll Need


  • Pressure washer, with a decrease setting, or garden hose with a hose attachment
  • Gloves 
  • Safety goggles 


  • Scrub brush
  • Manufacturer-approved cleaning solution with Mildewcide 
  • Manufacturer-approved sealant and/or stain
  • Clothes you don’t mind getting stains on
  • Optional: Manufacturer-approved color protection coat with an ultraviolet stabilizer


  1. Clean the Wood and Prevent Mildew

    Using a pressure washer on a lower setting to clear mud and other debris will help you start with a clean slate. If you don’t have a pressure washer, a garden hose with an attachment and scrub brush will also work. 

    Mold and mildew are always a risk when living in a humid area however, you can prevent massive growth by using a cleaner that includes Mildewcide. This will help keep your pressure-treated wood in the best shape. You can either check with the manufacturer of the pressure-treated wood for the right sealant or your local hardware store should be able to help you.

    Spray down the wood area and then let it soak for the recommended time, typically 20 minutes. Then rinse the deck with the pressure washer or a garden hose. Make sure that your deck is completely dry before moving onto the next step. 

  2. Seal and Stain Your Wood

    To prevent your boards from cracking, expanding, and shrinking from rain, it’s important to make sure that you seal it with a stain. However, it’s vital that your wood is completely dry before sealing or staining it. You can test this with dropping a few water droplets onto the wood. If it quickly absorbs (within two minutes) the water, you are good to go. If not, try the droplet test about two to three days later to ensure that your wood is dry. Once the wood is completely dry, protect certain areas of your home and yard from getting any stain on them by using plastic tarps. 

    Next, apply the stain by using a large paint brush, roller, or sprayer. The application method you choose is up to the homeowner but it’s recommended to use the method that feels most comfortable for you and achieves the look you want. 

    Allow it to dry and come back to see if you need a second coat or spot check. Most stains are good for one coat but depending on the look you want-you may want to give it a second go. You can use the water droplet test mentioned above to check if it’s ready for a second coat. Repeat the staining process if needed. If you want to keep the color of your wood from fading fast, use a color protection coat that can help by using a water-repellent finish with an ultraviolet stabilizer. 

    Allow a full two days for your stain to be complete, repeat the water droplet test before allowing family and pets use and enjoy your pressure-treated wood fixture.

  3. Keep a Preventive Care Schedule

    Inspect your pressure-treated wood fixture after every summer and every winter. Look for any missing nails, cracking or mildew build up. Catching minor damage early can prevent it turning into something larger and more expensive later. Skip future hassle and do a quick inspection. That includes accounting for all the fasteners and connectors, ensuring that they are securely in place.