How to Preserve Pressure Treated Wood

Pressure-treated wood contains arsenic.

Pressure-treated wood weathers well and is impervious to insect infestation, but contains arsenic. This chemical is highly toxic to humans. Many outdoor wood playgrounds and decks are constructed with pressure-treated wood. Controlling the transference and leaching out of arsenic is imperative. Coating the wood with a penetrating sealant helps, but it needs to be done every one or two years for optimum protection. A few hours of work will protect you and your family from the effects of arsenic exposure.

Things You'll Need

• Safety glasses
• Gloves
• Hose
• Dish soap
• Bucket
• Long-handled scrub brush
• Wood sealant
• Paint tray
• Paint brush or roller
• Drop cloths

Instructions

Cleaning the Wood

1. Rinse the wood with clear water from a garden hose. Use a spray nozzle attachment to reach overhead areas.

2. Mix 1/2 cup of dish soap with 2 gallons of water in a large bucket. Scrub the wood with the cleaning solution and a long-handled scrub brush.

3. Rinse the soap using a garden hose. Let the wood dry for a day or two before applying sealant.

Sealing the Wood

1. Position drop cloths over surfaces and plants to keep sealant from dripping onto them. Remove any hardware if it is a playground set.

2. Mix a can of water or oil-based wood sealant and pour it into a tray. Use a paint brush or roller to apply a layer to the wood. Let the surface dry for an hour or two.

3. Add a second layer of sealant to the wood surface. Remove the drop cloths and let the wood dry for 48 hours. Reattach any hardware that had been removed for sealing.

Tips & Warnings

• Do not sand or power-wash the surface of pressure-treated wood. Thurston County, Washington Public Health and Social Services states, "Sanding will scatter particles of arsenic in the air. Pressure-washing could increase the leaching of arsenic out of the wood."

• Wear safety glasses and gloves when working with pressure-treated wood.

References

• Thurston County, Washington Public Health and Social Services: Pressure-Treated Wood

Resources

• Dartmouth Medicine: Dangers of Arsenic Exposure