Is Pressure Treated Wood Safe for Indoor Use?

The quick answer is yes — pressure-treated lumber is safe for nearly any indoor application, except cutting boards and countertops. Some people find pressure-treated lumber installed in their homes and wonder if it could be harmful. The good news is, there's no risk of leaching or off-gassing with modern pressure-treated wood.

But that leads to another question: Why would you use pressure-treated lumber indoors? Pressure treatment is designed to protect wood from outdoor elements that cause rot, decay, and insect infestation. The wood is typically shielded from these risks inside a home unless it's regularly exposed to moisture, like in areas with leaks or around windows.

In specific cases, pressure-treated wood is chosen for indoor use. For instance, some bathroom subfloor panels are treated since they may experience consistent moisture exposure. Builders may also use borate-treated lumber, such as ProWood® Borate, for sill plates in regions with common termite infestations. In areas with extreme termite risks — like the U.S. Gulf Coast and Hawaii — the entire structural shell of a building might be constructed using ProWood Borate or similar borate-treated wood products.

Aside from these examples, there’s generally no need to use pressure-treated lumber indoors.