Wind, Earthquake & Weather Resistance
In areas susceptible to severe weather conditions, builders and designers are challenged with creating structures that will withstand the forces of nature. While regionalized building codes address the necessary design requirements, APA provides additional resources and details construction practices that help homes to perform even better against hurricanes, high winds, severe moisture and earthquakes.
Plywood and OSB Sheathing Boost Structural Strength
The overall strength of a building is function of all of the components – walls, floors, roof, and foundation – working together as a unit. When an earthquake or high wind strikes the house, the walls and roof bear the brunt of these forces. A fully sheathed wall of plywood or OSB, properly connected to the foundation below and roof above, is a strong barrier that resists the persistent forces of wind and earthquakes. Laboratory tests and field evaluations show that sheathing with plywood or OSB can help make a house two to three times more able to withstand high winds and earthquakes.
APA Issues Tornado Damage Report and Design Recommendations
Damage observations conducted by APA after the April 16, 2011 tornados in North Carolina and the powerful EF-4 and EF-5 storms that struck Tuscaloosa, Alabama on April 27 found that a lack of attention to detail along the uplift load-path often leads to weakness on the route through which high-wind forces must travel within the framing and into the foundation. Following a review of the findings, the Association has published a set of construction recommendations for improving tornado or hurricane resistance in light-frame wood construction.
The damage assessment report by APA Engineered Wood Specialist Bryan Readling, P.E., Tornados of the South: Structural Performance of Newly Constructed Homes in North Carolina, Alabama, and Georgia, Form SP-1154, is now available as a downloadable PDF.
The design recommendations are detailed in a new guide, Building for High Wind Resistance in Light-Frame Wood Construction, Form M310. Both the report and the design recommendations are available as PDF downloads from the APA Publication Library.
Protect Your Home from Windstorm Damage with Hurricane Shutters
Shutters over large windows and glass doors can help prevent windstorm damage. The APA publication Hurricane Shutter Designs, Form T450, includes five hurricane shutter designs with recommendations for a variety of window and door openings in masonry and wood-frame buildings. Designs include illustrations, materials lists, and step-by-step instructions. Details are also available for Latin America in Spanish language.
Hurricane Shutter Design Considerations for Florida, Form T460, is a regionalized version of the Hurricane Shutter Designs publication specific to Florida.
Prevent Damaging Moisture Infiltration
Designed to provide builders and homeowners the construction guidelines they need to protect their homes against damaging moisture infiltration, the Build a Better Home program from APA encourages better building practices for the key elements of a residential structure: roofs, walls and the foundation. Visit www.BuildaBetterHome.org for simple construction details, tips and videos on building moisture-resistant homes.
More APA Resources for Building Safe, Durable Homes
APA offers hundreds of publications containing detailed technical information for architects, builders, code officials, engineers, specifiers, and others in the trade. Below are a few of the many APA publications that address wall bracing and other considerations for designing and building structures that can safely resist the forces of nature, including the lateral loads that result from high-wind events and earthquakes. Click on any title to download a free PDF copy. To view all APA publications, visit the online APA Publications Library.
- Design for Combined Shear and Uplift from Wind, Form SR-101, provides designs for utilizing wind uplift resistance capabilities from wood structural panels, in addition to resisting lateral shear forces and wind pressure perpendicular to the wall.
- Introduction to Wall Bracing, Form F430, explains code bracing requirements in easy-to-understand terms and answers common bracing questions.
- Brace Walls with Wood, Form G440, provides additional wall bracing information, including narrow bracing options that incorporate fully sheathed walls for greater design flexibility.
- Introduction to Lateral Design, Form X305, explains how to design wood-frame buildings to withstand the lateral loads typical of high wind and seismic zones.
- Diaphragms and Shear Walls, Form L350, provides design and construction recommendations for engineered diaphragm systems in floor, shear wall, and roof systems.
- Design Concepts for Building in High Wind and Seismic Zones, Form W650, describes how lateral loads act on wood framing systems, and how construction detailing and fasteners affect the ultimate performance of a structure in high wind and seismic zones.
- Wind-Rated Roofs: Designing Commercial Roofs to Withstand Wind Uplift Forces, Form G310, presents tested assembly details for roof systems with APA wood structural panels used as substrate that meet classifications of FM Approvals or of Underwriters Laboratories.
- Technical Topics: Wind Resistance of Wood Structural Panel Sheathed Walls, Form TT-110, includes comprehensive information for wind resistance of light-framed walls sheathed with plywood or OSB using the methodology of the 2012 IBC, Table 2304.6.1 and the 2012 IRC, Table R602.3(3).
- Special Report: Hurricane Katrina, Form SPE-1125, assesses the structural performance of wood-frame buildings in severe weather conditions based on investigations following the 2005 hurricane.
- Builder Tips: APA Narrow Wall Bracing Method Framing Tips, Form F435, highlights essential details for constructing the APA Narrow Wall Bracing Method around garage openings.
- View more related APA publications available for free download on the Performance Walls Resources page.
Learn More about Severe Weather PreparednessThese national organizations provide information on severe weather preparedness, home safety, and important weather-related factors to consider when buying or building a new home:
Learn the Bracing Basics from APA
For simple solutions for code-compliant wall construction, visit PerformanceWalls.org, your leading resource for wall bracing and building safe, durable and energy-efficient walls.
- APA System Report: Design for Combined Shear and Uplift from Wind
- PDF 491K, Free Download
- Tornados of the South
- PDF 1.2MB
- Special Report: Hurricane Katrina
- PDF 1.7MB
APA Simplified Wall Bracing Method
This free APA System Report explains how to use continuous plywood or OSB sheathing for a more flexible, streamlined approach to code-compliant wall bracing. (For an overview of the benefites of the APA Simplified Bracing Method, view Simplified Bracing Method Streamlines Design.)
Guide to the 2012 Bracing Provisions
Latest wood wall bracing guide provides an explanation of the lateral bracing provisions of the 2012 IRC.