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How to Take Care of Pressure-Treated Lumber

Posted 6 June 2022 7:29 PM by ProWood

Whether you are building a new deck or fence, or just getting your current one ready for the season, learn how to protect your pressure-treated lumber against natural rot and decay to enjoy it for years to come.




Mildew Growth

When wood gets frequently exposed to humid conditions, mildew growth will occur. To clean current buildup and slow down the production of future growth, give it a good scrub with a cleaner containing mildewcide.

Shrinking and Swelling

Continuous water absorption and loss in treated wood can cause natural defects like twisting, cupping, warping, checking, and splitting to develop. It is best to apply a water-repellent sealant or a semi-transparent stain (specific for pressure-treated wood) to reduce the water movement within the boards. Note: you need to make sure your project is completely dry before applying the stain/sealer.


Ultraviolet Protection

To prevent the original color from fading, apply a water-repellent finish that contains an ultraviolet stabilizer for treated wood. This step will not prevent fading but will slow down the process of discoloration.


Yearly Maintenance Tips

Here are some application tips for cleaning and sealing:


  1. Applying a water-repellent sealer or semi-transparent stain: Sprinkle a few drops of water on the surface to test the level of dryness. If the wood immediately absorbs it, you can apply the stain/sealant. If the wood does NOT within 2-3 minutes, wait a few days and then test again before applying the stain/sealant.  

  2. We do not recommend using a conventional multi-coat paint system or varnish. Also, we do not recommend sanding pressure-treated wood. 

  3. You may be able to clean and recoat every two years depending on the amount of direct sun exposure, foliage coverage, and moisture that the wood receives each year. If you decide to wait two or more years to clean/brighten, you may need to use a power washer.


Maintenance on your treated deck, fence, pergola, or any other outdoor structure is essential to look its best for years to come. We know homeowners and builders prefer ProWood because it maintains its natural beauty year after year and is treated to deter fungal decay and termite attacks. Find a dealer near you!



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