Hardwood Flooring February March 2018

AT THE SITE

By Mark Halverson

Better Floor Performance

STARTS WITH A SOLID SUBFLOOR SYSTEM

Beautiful hardwood floors are an investment expected to last a lifetime. To ensure the best long-term performance and appearance, careful attention must be given to proper subfloor installation and mitigating moisture risks. Proper installation starts with specifying and installing the right subfloor materials. A variety of floor framing and wood structural panel products can be used in floor construction. To select the appropriate products and floor design, it’s important to consider the predicted loads, the structural requirements, and compatibility with the finished floor requirements. Quality through and through Hardwood flooring is most commonly installed over a single layer of tongue-and-groove combined subfloor-underlayment or sheathing-grade panels. APA Performance Rated Panels are manufactured to meet performance criteria for specific designated construction applications, as defined in the Voluntary Product Standard PS 2-10, Performance Standard for Wood- Based Structural-Use Panels. The standard applies to plywood and oriented strand board (OSB) panels. Plywood may also be manufactured to the prescriptive provisions of Voluntary Product Standard PS 1-09 for Structural Plywood. The standards are developed and maintained cooperatively by the wood structural panel industry, user groups, and the U.S. Department of Commerce, with APA –The EngineeredWood Association serving as sponsor. In Canada, APA-trademarked OSB is manufactured in conformance with CSA-0325. The maximum joist support spacing and corresponding span rating is identified in Part 9 of the National Building Code of Canada (NBCC). APA- trademarked plywood is certified to CSA-0151, Canadian Softwood Plywood; CSA-0121, Douglas-Fir Plywood; or CSA- 0153, Aspen/Poplar Plywood. Part 9 of the NBCC specifies minimum panel thicknesses for these products at common joist spacing. The certification trademark that appears on the product is the manufacturer’s assurance that the product conforms to the standard indicated on the mark (Figure 1). Several independent agencies provide quality assurance services to U.S.

Photo courtesy of APA

and Canadian manufacturers of which APA –The Engineered Wood Association, TECOCorporation, and Timber Products Inspection are three major providers. Use the trademark to specify the right panel for the job Performance rated panels, such as APA Rated Sturd-I-Floor and APA Rated Sheathing, are easy to use and specify for floor applications because the maximum recommended spacing of floor joists – or span rating – is included in each trademark stamp. Panels are manufactured with span ratings of 16”, 20”, 24”, 32”, and 48”. These assume use of the panel continuous over two or more spans with the long panel dimension or strength axis across supports.

the magazine of the national wood flooring association

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