The new CLSAB Treated Wood Program (TWP) requires verification that treated wood products have been produced to standards set by the Canadian Standards Association. Qualifying products will be marked with a stamp or tag similar to a lumber grade stamp. This stamp/tag will indicate that the product has been inspected and meets the standards of the CLSAB TWP, which CSA standard it meets, and which agency has inspected the treating plant. These standards will be incorporated into Canadian Building Codes in the same way structural lumber standards are now a part of building codes.

Since treated wood products have a distinctive colouring, a stamp is not always visible so a tag is often used.

To see a sample preservative treated wood tag and what it means, click here.

To see sample preservative wood tags from CLSAB-accredited agencies, click here.