Pressure treated wood is plywood that has undergone a unique pressurized process that gives the wood a higher density, making it harder for any rot, water, mold, or insects to infiltrate. The method uses pressure to push chemicals into the wood, allowing the substances to be evenly distributed into the plywood. This process allows for control over how the chemical is used, and even distribution makes for a better quality and more substantial material.
Pressure treated wood and heated treated wood are NOT the same thing, however, these two types of treatment do have some crossover. Pressure treated wood is usually reserved for wood that may come in to contact with excessive moisture.
There are three types of pressure treat plywood:
- Borate: Borates are sodium salts that are then used in a water-based solution. This chemical helps keep wood color while protecting against mold, insects, and general breakdown and is best for dry locations.
- Alkaline Copper Quaternary: This option is the most environmentally friendly. Like Borates, it protects against mold, insects, and general breakdown. This option changes the color of the wood to a darker brown tone, but no arsenic or chromium is contained in this preservative.
- Noncombustible Wood: This type of pressure-treated wood has been treated with a fire-retardant chemical before it is pressurized. This will help with flammability but does not entirely eliminate the risk. However, it is not advised to be painted because it may affect its performance.
Pressure treated plywood is made in a process. In this process, the wood will go into a particular cylinder chamber called a retort. The retort machine will seal and depressurize to get as much air as possible from the wood’s cell. The chamber will then be flooded with chemicals, and pressure will be applied for a long time. What it is being used for will determine its “retention level,” for example, if the wood needs a higher retention level, it will be left in the chamber for more time. Once the treatment is finished, it will be placed somewhere to dry before delivery entirely.
There are several misconceptions surrounding pallets and pressure treatment. One of those common misconceptions is that all wooden pallets are pressure treated. Many pallets are made from untreated wood, which may be more susceptible to decay and pest infestation from not undergoing this process.
Alternatives to pressure treated pallets such as, heat-treated pallets that are subjected to a heating process to eliminate pests and sterilize wood are available and are often marked with the initials “HT” and a stamp or brand indicating the treatment.
Ways to determine if a pallet has been pressurized:
One method is to check for visible signs of treatment, such as a greenish tint or minor puncture marks on the wood surface. Another way is to look for makings or labels on the pallet that indicate pressure treatment, however, not all pressurized wood pallets are labeled and not all pallets wood is pressure treated, so it’s best to check with the supplier.
