Gradestamp images are included at the end of this document for reference.

1. Third-party inspection agency

   Structural panels are identified with the mark of a qualified inspection and testing agency. TECO is an accredited agency recognized and accepted in the United States by the International Accreditation Service (IAS) and in Canada by the Standards Council of Canada (SCC). TECO TESTED® is TECO’s certification mark registered with the U.S. Patent and Trademark Office (USPTO) and the Canadian Intellectual Property Office (CIPO). A lower case “c” is place before the certification mark to identify product for Canada.

2. Product standards for structural panels

   PS 1 and PS 2 are nationally recognized Voluntary Product Standards developed under procedures published by the U.S. Department of Commerce. U.S. building codes requires that structural panels for applications in the U.S. comply with either PS 1 or PS 2. PS 1-07, Structural Plywood, establishes requirements for structural plywood. PS 2-04, Performance Standard for Wood-Based Structural-Use Panels, establishes requirements for structural wood-based panels such as oriented strand board (OSB), waferboard and certain types of plywood. For structural products to be used in Canada, the National Building Code of Canada requires that they comply with CAN/CSA O325.0, Construction Sheathing. CSA O325 establishes requirements for wood-based panels such as oriented strand board (OSB), waferboard and certain types of plywood.

3. Bond classifications

   Exposure 1 and Exterior identify the bond classifications for structural panels. An Exposure 1 classification means that the panels are suitable for uses not permanently exposed to the weather; i.e., intended to resist the effects of moisture on structural performance due to construction delays or other conditions of similar severity. An Exterior classification means that the panels are suitable for repeated wetting and redrying or long-term exposure to weather or other conditions of similar severity.

4. Panel grades

   Structural-use panels are manufactured and designed for different applications and identified as such. Panels may be identified as single floor (combination of subfloor and underlayment), sheathing (roof, subfloor, and/or wall), Structural 1 sheathing (roof and/or wall), underlayment, concrete form, siding, or marine. In addition, plywood panels are often identified with regard to the quality of the face and back veneers (e.g. A-C, C-D, etc). TECO has USPTO and CIPO registered marks for specific panel applications such as FLOOR SPAN® (single floor), SHEATHING SPAN® (sheathing), and SPECIALTY SIDING® (siding).

5. Group classification (for plywood only)

   For plywood products manufactured in North America, the species group classification (number 1 – 5) is determined directly by the wood species used in the panel face and back veneers or – for some products – by performance testing. For plywood products manufactured outside of North America, most plywood products are group classified by performance testing. Lower group classification numbers represent greater product strength, with Group 1 being the strongest. Most commonly, sanded plywood products intended for a variety of industrial and construction uses are identified only with a group classification, not with a span rating.

6. Manufactured nominal thickness

   Structural-use panels are manufactured in a variety of thicknesses ranging from ¼ to 1-1/4 inches. In the U.S., PS 1 and PS 2 panels are identified with the nominal thickness English units. In Canada, CSA O325 panels are identified with a nominal thickness Metric units rounded up to a multiple of 0.5mm. For PS 1 unsanded, touch sanded, and overlaid panels and all PS 2 panels, a tolerance of + 1/32” is allowed on the trademark- specified thickness of 13/16” and less and + 5% of the trademark-specified thickness for panels thicker than 13/16”. Sanded PS 1 panels are allowed a tolerance of + 1/64” for trademark- specified thicknesses of 3/4” and less and + 3% of the trademark-specified thickness for panels thicker than 3/4”.

7. Span rating

   Panels may be identified with a span rating. The span rating identifies the recommended maximum center-to-center support spacing1 under normal use conditions. Panels for which there is no span rating are identified by the largest species group number of the face and back, or by the span rating of the next thinner comparable panel. Depending upon the product, a span rating will consist of (1) or (2) numbers, with details as follows:

   • Single floor panels have a single-number (e.g., 20 oc, 24 oc, etc.) span rating (joist spacing).
   • Typical sheathing and Structural 1 sheathing have a two-number span rating (e.g., 24/0, 24/16, 32/16, 48/24, etc). For a two-number span rating, the number on the left identifies the span rating (truss or rafter spacing) if the panel is used in a roof application and the number on the right identifies the span rating (joist spacing) if the panel is used in a subfloor application. Panels with the number zero on the right are not allowed to be used in subfloor applications.
   • Sheathing grade panels are often used in wall applications. Some products are marked with a single-number span rating (e.g., Wall-16 or Wall-24). Alternatively, sheathing products with two- number span ratings may also be used in wall applications by referring to the span rating number on the left. If the number on the left is 16 or 20 (e.g., 16/0, 20/0, etc.), the allowable wall span rating (stud spacing) is 16 inches. If the number on the left is 24 or greater (e.g., 24/16, 32/16, etc.), the allowable wall span rating (stud spacing) is 24 inches.
   • In Canada, panel marks are comprised of an end use mark followed by a span mark (e.g., 1F20, 1R24/2F16, W24, etc.). End use marks specify the panel application as: 1F (single floor), 2F (subfloor requiring separate underlayment), 1R (roof sheathing), 2R (roof sheathing, requiring edge support) or W (wall sheathing). Span marks specify the recommended framing member spacing (e.g., 16, 24, 32, etc.).

8. Strength axis (OSB only)

   OSB panels are marked to identify the orientation with the greatest strength (strength axis). The strength axis is parallel to the flake or grain orientation of the panel face and back surfaces, which is generally aligned with the long panel dimension.

9. Mill number

   The mill number is assigned by TECO to identify the individual panel manufacturer. TECO mill numbers and corresponding manufacturer names are listed on the TECO website at www.tecotested.com.

10. Additional information

    Additional information may also be stamped on the panel by the manufacturer. Such information might include: “SIZED FOR SPACING”, “THIS SIDE DOWN”, “WALL ONLY”, manufacturer’s name or logo, net face dimension, tongue and groove, minimum edge and/or end spacing, etc. to assist in installation.

¹ Certain products may require additional panel edge support to achieve the maximum roof span rating. Consult the building code for additional requirements.

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