How does Pressure (ACQ) Treated Plywood differ from regular plywood?
In basic terms, pressure treated plywood is regular plywood that is placed inside a cylinder full of ACQi chemical. The chamber is sealed, and air is withdrawn to create a vacuum, which forces the chemical into the cells in the wood. After the treatment is complete, the plywood is removed, placed in a kilni and dried. There are various “retention levels” available in ACQ plywood, and the application dictates the retention level required. Pressure treated plywood that is in contact with the soil requires a higher retention level than plywood which is above gradei. The highest retention level is used for wood that is immersed in salt water. PSI uses only ACQ for treatment purposes. CCAi has been the industry standard for many years, and is still available. However, there is evidence that some of the arsenic in the CCA treated material can “leach” out of the wood and into the soil overtime. Since pressure treated wood is often used in children’s playgrounds, the dangers are obvious. For t
