How To Choose Pressure Treated Wood

Build beautiful outdoor projects with bug- and rot-resistant pressure treated wood

Keep wooden outdoor structures beautiful for years by building with wood treated to resist insects, mold and rot. This guide will walk you through the types and benefits of pressure treated (PR) wood.

Safety: Always wear gloves, eye protection and a dust mask when handling wood. Due to chemicals in pressure treated wood, never burn its sawdust or scraps; instead dispose in a landfill.

What Is Pressure Treating?

Pressure treating is a chemical process that helps wood withstand the elements and wards off insects, microorganisms and fungal decay.

The most common chemicals used to treat wood are Alkaline Copper Quaternary (ACQ), Copper Azole (CA), and Micronized Copper Quaternary (MCQ).

During the pressure treating process, wood is saturated with the chemical solution carried in water. The wood takes several months to dry and there may be some shrinkage and warping as a result.

It may be necessary to wait three weeks to six months prior to staining or painting the wood, depending on the climate where you live and the treatment process the wood has undergone. Ask a Home Depot associate for details about the lumber you select.
Pressure treated lumber can last 20 years or more, and most pressure treated wood comes with a limited lifetime warranty.  

Pressure Treating

ACQ/CA vs. MCQ Pressure Treated Wood

See details on the two primary types of pressure treated wood in the following chart.

pressure treated wood chart

Tip: Due to the large amount of copper found in pressure treated wood, standard steel fasteners will corrode up to five times faster than when used in untreated wood. Opt instead for galvanized or stainless steel fasteners and metal components.