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Roof Wind Designer Updated by National Roofing Contractors Association

Release Date: April 15, 2016

The National Roofing Contractors Association (NRCA) recently released an updated version of their online wind-load calculator, “Roof Wind Designer.” This free, web-based application is intended to provide roofing professionals with an easy way to determine roof systems' design wind loads for many commonly encountered building types subject to code compliance.

The application is based on the requirements of ASCE 7, Minimum Design Loads for Buildings and Other Structurespublished by the American Society of Civil Engineers (ASCE). ASCE 7 is the most widely used consensus standard for evaluating design wind loads for buildings and other structures. The “Roof Wind Designer determines roof systems’ minimum recommended design wind-resistance loads, which are derived from the building’s design wind loads, taking into consideration a safety factor in reliance of ASTM D6630, Standard Guide for Low Slope Insulated Roof Membrane Assembly Performance. Using these minimum recommended design wind-resistance loads, users can select appropriate wind-resistance classified roof systems and edge-metal flashing systems.”

The application includes the ability to address wind loads applicable to perimeter edge-metal flashing system design, to address compliance with ANSI/SPRI ES-1, Wind Design Standard for Edge Systems Used with Low Slope Roof Systems, published by the Single Ply Roofing Industry (SPRI). The application allows the user to select appropriate wind-resistance classified roof systems and edge-metal flashing systems. However, the application is limited to building heights less than 60 feet and roof systems with slopes up to 12:12 and hip roofs with slopes up to 6:12.

The Roof Wind Designer was developed in cooperation with the Midwest Roofing Contractors Association and North/East Roofing Contractors Association. The wind load calculator tool is available at

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The information contained in this publication was obtained from sources believed to be reliable. ISO Services, Inc., its companies and employees make no guarantee of results and assume no liability in connection with either the information herein contained or the safety suggestions herein made. Moreover, it cannot be assumed that every acceptable safety procedure is contained herein or that abnormal or unusual circumstances may not warrant or require further or additional procedure.

COPYRIGHT ©2016, ISO Services, Inc.