Pressure-treated Lumber

The standard workhorse of the deck industry, pressure-treated lumber is so named due to the process in which water-borne insecticide is introduced (forced) into the fibers of the wood via hydraulic pressure. This is typically done in bulk quantities in converted railroad tank cars. The chemical treatment prevents insects (such as termites) and smaller organisms (bacteria) from corrupting the wood and causing its rot and decay. Treated lumber can last for years in contact with the ground and has proven very effective in prolonging the longevity of outdoor wood structures.

The chemicals used to treat the lumber have changed. Prior to 2004, the lumber was CCA treated (chromated copper arsenate). This substance has been discontinued because of its arsenic content, and replace with ACQ (alkaline copper quaternary) which is more environmentally friendly and just as effective.

Although any lumber can be pressure-treated, the process is typically used on Southern Yellow Pine (SYP) which is a very strong pine wood used in framing construction. It’s used in all areas of the deck – including the framing, decking surface and railings.

Pressures-treated lumber has the recognizable pale green hue seen everywhere. While it resists rot and decay, it does not remain new-looking for long, being subject to mold, which may begin within a couple of years to turn it first to light, then dark grey.
For exposed deck and rail surfaces, it is recommended that a good water-repellant treatment be applied after construction is complete. This helps the wood weather the ravages of water and sun which still impact the wood in spite of its resistance to rot and decay. Many wood-preservative stains are available in a variety of colors as well. Just Decks applies a one-time complimentary treatment of “Thompsons Water Seal” to the deck surface and railings if constructed out of wood.