Recognizing and understanding quality marks on treated wood can be confusing to users. That's why WWPI developed the CheckMark® Identification Program to help recognize products that meet national consensus standards for preserved wood treating.
The distinctive CheckMark logo, which appears on end labels of preserved wood products, signifies the wood has been produced under the oversight of a third-party agency that has been accredited by the American Lumber Standard Committee (ALSC). These agencies are required to meet the American Wood Protection Association (AWPA) U-1, M-2 and M-22 Standards for inspection to ensure the treating companies meet the requirements for preservative penetration, retention and quality control.
There are three agencies in the West accredited by ALSC to provide third-party inspection of preservative-treated wood products. They are:
In the southern U.S., the Southern Pine Inspection Bureau and Timber Products Inspection provide these services to treating companies.
Understanding End Labels
Most preserved wood products sold in retail locations carry an end label affixed to each piece that contains important information about the wood, the preservative treatments used and where it was produced. While these labels may appear differently based on the manufacturer, all contain the same elements as shown.
The back side of the end label typically contains information on the warranty offered for the product. This information is accompanied by a website address, where you can read more detailed information about the warranty
It is recommended you save some of the labels, along with invoices or other sales paperwork for your project, should you need to make a claim under the warranty.
To comply with all building codes, preservative-treated wood must be marked with an end tag showing an accredited ALSC agency.
The International Building Code states: “Wood required by Section 2304.11 to be preservative treated shall bear the quality mark of an inspection agency that maintains continuing supervision, testing and inspection over the quality of the preservative treated wood. Inspection agencies for preservative treated wood shall be listed by an accreditation body that complies with the requirements of the American Lumber Standard Committee (ALSC) Treated Wood Program, or equivalent. The quality mark shall be on a stamp or label affixed to preservative-treated wood.”
Preserved wood products manufactured in the West are treated with AWPA-approved preservatives and will carry the CheckMark along with the logo of the ALSC authorized third-party inspection agency.