This question relates to an International Residential Code requirement that has recently been adopted in some states. It requires fire protection of most lightweight floors, including open web wood trusses, I-joists and lightweight steel framing. APA has recently added several new assemblies to our System Report SR-405. We will have a webinar dedicated to that topic in May. Stay tuned; we will post details on our website.

Yes, cross-laminated timber or CLT is indeed an engineered wood product. We didn’t cover it in this program since this series of educational webinars primarily is for the wood products distributor. CLT is new to the market in North America and is not sold through typical distribution channels, but rather on a project-by-project basis.

Note that there are currently four manufacturers of CLT in North America, and they all manufacture, or plan to manufacture, product to the APA-developed CLT ANSI Standard. All four producers are members of APA. Visit our CLT page for additional information.

Visit the manufacturer directory on our website for a full listing of APA member-manufacturers and the products they produce. You can search by product, manufacturer, or mill number.

Visit the Staff Contacts page on our website for a listing of all the local Engineered Wood Specialists.

Engineered wood products (EWPs) are made of wood (lamina, strands or veneers) and synthetic adhesives. The adhesives in EWPs are functionally similar to cured plastic resin, which means they could last indefinitely. Construction plywood has been used since the early 20th century and OSB has been in use for more than 30 years. Laboratory and outdoor exposure studies have shown that OSB used in an appropriate applications, should have long term performance equivalent to other wood construction materials.

Adhesive certification standards and methods are specific to product type. For structural plywood, the standard in the US is US Voluntary Product Standard PS 1 and the required tests include cold water vacuum pressure and boil cycles and a heat (fire) exposure test. For OSB, the standard is US Voluntary Product Standard PS 2 and includes structural tests, both dry and following wetting cycles and a small specimen test following a hot-water vacuum pressure cycle followed by redrying.

APA has developed the APA Wall Bracing Calculator, a tool intended to simplify the design of residential structures that comply with 2009 and 2012 International Residential Code (IRC) wall bracing requirements. Note: this calculator is intended for use by experienced designers that are familiar with wall bracing.The APA has developed The APA Wall Bracing Calculator, a tool intended to simplify the design of residential structures that comply with 2009 and 2012 International Residential Code (IRC) wall bracing requirements. Note: this calculator is intended for use by experienced designers that are familiar with wall bracing.

With the APA Wall Bracing Calculator a designer can:

• Create a project and identify its pertinent details.
• Pictorially identify and calculate the bracing requirements of each braced wall line.
• Pictorially identify, qualify and locate each bracing segment on a given wall line.
• Export the results to a printable document.

APA does not provide design software for engineered wood floor systems, roof systems or beam sizing, but many APA member-manufacturers do provide proprietary design software for use with their products. Check with your supplier for information on what is available.

You can find more than 250 free CAD details for wood-frame construction, including many APA member products at www.apacad.org.

APA is a nonprofit trade association that has grown and evolved with the engineered wood industry. APA was founded in 1933 as the Douglas Fir Plywood Association, and was later recognized as the American Plywood Association. In 1994, APA changed its name to APA – The Engineered Wood Association to better reflect the range of products manufactured by APA members and the international scope of the Association. The letters “APA” were retained in the name because of their longstanding recognition in the marketplace.

APA-rated wood structural panels, including plywood and oriented strand board (OSB), are manufactured to meet stringent product standards, like Voluntary Product Standard PS 1, Structural Plywood and Voluntary Product Standard PS 2, Performance Standard for Wood Structural Panels. Because wood products manufactured under these standards are designed for construction applications governed by building codes, they are manufactured only with moisture-resistant adhesives that meet Exterior or Exposure 1 bond classifications. These adhesives, typically phenol formaldehyde and polymeric diphenylmethane diisocyanate (pMDI), are chemically reacted into stable bonds during pressing. The final products have such low formaldehyde emission levels that they easily meet or are exempt from leading formaldehyde emission standards and regulations, including the U.S. HUD Manufactured Housing Standard, the California Air Resources Board (CARB) Air Toxic Control Measure for Composite Wood Products, and the Japanese Agricultural Standards (JAS).

We do not have published reports or data on VOC (volatile organic compound) emissions from APA-trademarked engineered wood products. All woods contain naturally occurring organic compounds, which result in some volatile organic emissions. These compounds give wood color, smell and, in many cases, some resistance to decay. Much of the veneer used to manufacture plywood today is from the outer portion or sapwood, which has less of these organic compounds. In general, we would consider engineered wood products including structural plywood to have low volatile organic compound emissions.

Note that evaporation resulting from the drying and curing process greatly reduces emissions of the naturally-occurring organic substances from plywood and LVL veneer, flakes/wafers for OSB and strand lumber and laminates for structural glued laminated timber.