Panel Grade — The term “grade” may refer to panel grade or veneer grade. Panel grades are generally identified in terms of the veneer grade used on the face and back of the panel (e.g., A-B, B-C) or by a name suggesting the panel’s intended end use (e.g., APA RATED SHEATHING, APA RATED STURD-I-FLOOR®, APA RATED SIDING, UNDERLAYMENT).
Span Rating — Two numbers separated by a forward slash. The left-hand number is the maximum recommended center-to-center spacing for supports in inches when the panel is used for roof sheathing with long dimensions across supports. The right-hand number is the maximum center-to-center spacing of supports in inches when the panel is used for subflooring with the long dimension across supports. The span rating on APA RATED STURD-I-FLOOR, underlayment, and APA RATED SIDING panels appears as a single number indicating center-to-center stud spacing. The span ratings for APA RATED STURD-I-FLOOR and underlayment panels, like those for APA RATED SHEATHING, are based on application of the panel with the long dimension or strength axis across three or more supports.
Product Standard — An industry product manufacturing or performance specification. Voluntary Product Standard PS 1, Structural Plywood, was developed cooperatively by the plywood industry and the U.S. Department of Commerce. Voluntary Product Standard PS 2, Performance Standard for Wood Structural Panels, establishes performance criteria for specific designated construction applications. ANSI/APA PRP 210, Standard for Performance-Rated Engineered Wood Siding, was developed by APA under the national consensus process of the American National Standards Institute (ANSI) to provide qualification and marking requirements during manufacture. APA PRP-108, Performance Standards and Qualification Policy for Wood Structural Panels, was developed by APA to provide qualification and marking requirements on APA RATED SIDING products.
Tongue-and-Groove — A system of jointing in which the rib or tongue of one member fits into the groove of another. Tongue-and-groove edges can eliminate the need for blocking beneath panel edges for support.
Bond Classification — Exposure ratings for APA wood structural panels may be Exterior or Exposure 1. The classifications are based on the severity and duration of weather and moisture exposure the panels are designed to withstand, and the wood materials and adhesives used in manufacture.
Decimal Thickness Declaration — This number lists the thickness of the panel in decimal format. This value is generally at or near the lower tolerance specified in the appendix of PS 1 or PS 2.
Mill Number — Manufacturing mill identification number.
Performance Category — A panel designation related to the panel thickness range that is linked to the nominal panel thickness designations used in the International Building Code (IBC) and the International Residential Code (IRC). Find additional information on the historical derivation of Performance Category expression of panel thickness labeling requirements in APA publication Panel Thickness Tolerances and Labeling, Form TT-054.
Siding Face Grade — Grade identification of siding face, based on number of repairs and appearance characteristics.
Species Group Number — Classified according to strength and stiffness under manufacturing standard PS 1 into Groups 1 through 5. Group 1 woods are the strongest, Group 2 second strongest, and so on. Typically used when no span rating is noted.
HUD Recognition — Recognition of wood-based performance-rated panels is contained in Use of Materials Bulletin UM-40c.
Panel Type, Canadian Standard — Some APA panels are manufactured to both U.S. and Canadian standards, and carry a dual mark, as shown in the RATED SHEATHING mark above. Other panels may carry a single mark for either the U.S. or Canadian standard.
Span Rating, Canadian Standard — Span rating and end-use designation for use in Canada. In the Canadian span marking, the “R” signifies roofs and the “F” represents floors: 1F for single floor and 2F for subfloor.
Adhesive Type, Canadian Standard — Adhesive type is required by Canadian building codes. Bond classifications Exterior and Exposure 1 meet Exterior Type Adhesive according to CSA O325.
Canadian Construction Sheathing Standard
Panel Face Orientation Indicator
