Help Desk Recommendations for Refinishing APA Siding Products
With summer around the corner we’re beginning to receive inquiries about recommendations for refinishing APA siding products.
Help Desk Question: Marine-grade plywood as exterior siding
Question: Is it appropriate to use Marine-grade plywood as an exterior siding product?
Engineered Wood Siding Standard Approved for Reference in the 2012 International Codes
A new American National Standard for engineered wood panel siding, Standard for Performance-Rated Engineered Wood Siding (ANSI/APA PRP-210), was approved for acceptance into the 2012 International Codes at the 2009 Code Development Hearings in Baltimore, MD. The standard was developed by APA under the consensus process of the American National Standards Institute (ANSI) and was approved for publication by ANSI in December 2008.
2008 APA Publications Index Now Available
The APA Publications Index, Form B300 NN, has been updated. The revised 2008 index provides a complete listing of APA design and construction guides, product guides, builder tips, case histories, industrial publications and other materials available from the Association.
Help Desk Question: Should I-joists be treated at soffit/eave locations?
Question: What approved methods of weatherization exist for I-joists that are extended for soffit and eave locations on a roof structure? Do you need to have an enclosed soffit and eave, or can they be painted?
New Engineered Wood Construction Guide
APA just issued the 2007 Engineered Wood Construction Guide, the major reference manual for using engineered wood products in residential and commercial construction.
New Publication Covers Sheathing and Siding Used to Resist Combined Shear & Uplift
APA just released a new Technical Note entitled, Wood Structural Panel Sheathing or Siding Used to Resist Combined Shear and Uplift, Form H335.
Help Desk Question: Is Building Paper Required by Code?
Question: Hasn’t the building code been revised to now require the use of building paper under all siding?
Help Desk Question: Refinishing Plywood Siding
Question: How would you recommend refinishing old plywood siding? How often should the plywood be refinished to best maintain the siding?
Answer: Any finish will begin to show its age after prolonged exposure to sun and weather. The weathering process can gradually erode the finish, cause it to become brittle and crack, lose its adhesion, fade, or mildew. Where the finish has weathered away, sunlight and moisture will erode and roughen the surface. For continuing satisfactory performance, it is important to maintain the finish. It is also important, however, not to refinish too often, especially when oil-based solid-color stains are used. If too many coats of an oil-based finish are applied, the finish becomes too brittle and will fail prematurely.
Help Desk Question: Requirements for weather-resistive barriers
Question: What are the requirements surrounding weather-resistive barriers over wood structural panel wall sheathing? Can this requirement be exempt?
Answer: Until recently, building code provisions and APA recommendations allowed omission of additional weather barriers over wood structural panel sheathing, which historically were recognized as water-repellent panel sheathing.
With changes to building practices and in an effort to reduce chances of moisture-related problems in wall cavities, APA revised its stance on the topic in 2001 to recommend the application of additional weather barriers in wall assemblies.
Explaining the Span Rating Designation
APA RATED SHEATHING, APA RATED STURD-I-FLOOR and APA RATED SIDING carry numbers in their trademarks called Span Ratings. These denote the maximum recommended center-to-center spacing in inches of supports over which the panels should be placed in construction applications. Span ratings are based on minimum 24-inch panel width and panel applied over minimum two spans.
Except for APA RATED SIDING panels, the Span Rating applies when the strength axis is across supports (long dimension unless the strength axis is otherwise identified). The Span Rating of APA RATED SIDING panels applies when installed parallel to supports.
