Tech Today

Treated wood and roof assemblies

In February, NRCA issued a Special Report, "Use of treated wood in roof assemblies." In the report, NRCA provides a brief background of its concerns with the use of the current generation of pressure-treated wood and offers specific interim recommendations intended to address the concern of corrosion relating to the use of treated wood.


Since the early 1930s, the most widely used chemical treatment for treated wood has been chromated copper arsenate (CCA) compounds. CCA-treated wood has proved to perform successfully in many applications, including as roof assembly components.

As of January 2004, wood preservers voluntarily removed CCA-treated wood from U.S. and Canadian consumer markets as a result of an agreement with the U.S. Environmental Protection Agency (EPA). EPA cited the arsenic and chromium contained in the CCA treatment as being possible environmental concerns when used in certain outdoor applications, such as furniture and playground equipment.