search
cart
facebook twitter linkedin youtube instagram Spotify Podcasts Apple Podcasts Spotify Podcasts Apple Podcasts
  • Sign In
  • Create Account
  • Sign Out
  • My Account
  • NEWS
  • TOPICS
    • Cool Roofing
    • Event News
    • Latinos in Roofing
    • Low Slope
    • Legal
    • Metal
    • Project Profiles
    • Roofing Supply Pro
    • Roofing Safety
    • Steep Slope
    • Sustainable Roofing
    • Technology
  • EXCLUSIVES
    • Best of Success
    • Contractor Profile
    • IRE Show
    • Roofing Contractor of the Year
    • Top 100
    • Young Guns
    • State of the Industry
    • Century Club
  • MULTIMEDIA
    • Videos
    • Podcasts
    • Interactive Spotlights
    • Roofing Quizzes
    • IRE Videos
    • Webinars
    • Photo Galleries
  • PRODUCTS
    • New Products
    • Featured Products
  • COLUMNS
    • Editor's Note
    • Exit Planning
    • Legally Speaking
    • Safety Advice
    • Technical Details
    • Guest Column
  • EVENTS
    • International Roofing Expo
    • Webinars
    • Best of Success Conference
    • Industry Events
  • DIRECTORY
    • Associations
    • Distributors
    • Manufacturer/Supplier
    • Business Services
    • Get Listed
  • MORE
    • Roofing Contractor eNews
    • Techos y Más Advisory Board
    • RC Store
    • Roofing Supply Pro
    • Custom Content & Marketing Services
    • Market Research
    • Sponsor Insights
    • Company Spotlights
    • Classifieds
      • Auctions
      • Business For Sale
      • Business Opportunities
      • Equipment For Sale
      • Positions Available
      • Products
      • Safety
      • Software
      • Services
      • Training
    • Contact Us
  • EMAGAZINE
    • eMagazine
    • Advertise
      • Media Kit
      • Editorial Calendar
      • Contact
    • Archive Issues
  • SIGN UP!

The Russo Report: Wind Uplift Solutions

By Michael Russo
April 8, 2009
There is still a common misconception in the design community that Factory Mutual (FM) I-90 represents winds of 90 mph. In fact, the standard requires the roof system to withstand 90 pounds per square foot (psf) of wind uplift tested pressure.

There is still a common misconception in the design community that Factory Mutual (FM) I-90 represents winds of 90 mph. In fact, the standard requires the roof system to withstand 90 pounds per square foot (psf) of wind uplift tested pressure.

There are actually many calculations that go into the wind design process-all based on the original ASCE-7 standard for building envelope pressures. Building location, height, ground roughness and other factors all enter into the wind uplift equation.

In general, designing for 90 psf is overkill except in high wind areas. However, I-90 is frequently rubber-stamped in up to 80 percent of roofing specifications where 75 or 60 psf would be adequate and more cost effective. Currently, for building design pressures up to and including 45 psf, using an FM safety factor of 2, Factory Mutual now requires the roof assembly to withstand the following tested differential ultimate pressures:
  • Field of Roof: 90 psf
  • Perimeter of Roof: 150 psf
  • Corner areas of Roof: 225 psf
For building design pressures up to 60 psf, using an FM safety factor of 2, Factory Mutual now requires the roof assembly to withstand the following tested differential ultimate pressures:
  • Field of Roof: 120 psf
  • Perimeter of Roof: 195 psf
  • Corner areas of Roof: 300 psf
In addition, roof assemblies over 90 psf are tested to these pressures on a 12-foot by 24-foot uplift testing table. The old method of simply increasing the roof-field fastener count by fixed percentages for perimeter and corner areas of adhered systems is no longer accepted for the FM field-of-roof ratings of 90 psf and higher.

As one can see from the charts above, the required uplift resistance at the corners of the roof is much higher than the field of the roof. This is because the roof edges were the determining factor in failures, according to FM’s and RICOWI’s research. However, there are other methods of strengthening the edges and corners of roof systems, such as using a “peel stop” on roofing membranes. (For more information on peel stops, visit www.spri.org.)

When these changes took place in 2006, only a handful of the multitude of fully adhered specifications were able to meet the new FM standards, and many roof system suppliers had to re-test.

One way to meet the new FM requirements and increase the “strength” of the roofing assembly is to specify a 1/2-inch pre-primed gypsum cover board directly fastened to the roof deck. In recent testing, a three-ply built-up roof (BUR) with 1.5 inches of loose laid polyiso insulation achieved an impressive FM rating of 315 psf - 15 psf higher than the elevated corner pressures required for an FM I-120 listing.

Similarly, a 45-mil, fleece-backed EPDM single-ply membrane fully adhered with hot asphalt tested at 285 psf. A number of membrane manufacturers have tested various types of gypsum cover boards with their adhered membranes and have achieved a variety of high uplift results.

Share This Story

Michael Russo is a contributing writer to Roofing Contractor. He can be reached at mikerusso1983@zoominternet.net. 
You must login or register in order to post a comment.

Report Abusive Comment

Blog Topics

Damato of the Day

Guest Blog

Recent Comments

Cambridge Heating And Cooling

Foundation Bolts Manufacturer and Supplier

Scratch Games

CDSCO Certification

Justin Bieber’s purple hoodie is an iconic piece...

Manage My Account
  • eMagazine Subscription
  • Sign Up for the eNewsletter
  • Online Registration
  • Manage My Preferences
  • Subscription Customer Service

More Videos

Sponsored Content

Sponsored Content is a special paid section where industry companies provide high quality, objective, non-commercial content around topics of interest to the Roofing Contractor audience. All Sponsored Content is supplied by the advertising company and any opinions expressed in this article are those of the author and not necessarily reflect the views of Roofing Contractor or its parent company, BNP Media. Interested in participating in our Sponsored Content section? Contact your local rep!

close
  • TAMKO Titan XL Shingles
    Sponsored byTAMKO®

    Built for Business: How Titan XT® Shingles Keep Proving Their Value

  • An overhead view of a residential block
    Sponsored byCBIZ CompuData

    From Spreadsheets to Strategy: How Roofing Companies Can Transform Financial Operations

  • Snow Guard Solutions for Metal Roofs by S-5!
    Sponsored byS-5!

    Safeguard Your Building: How Snow Guards Prevent Costly Roof & Property Damage

Popular Stories

The Home Depot is weighing a bid for GMS. The potential offer would pit the retail giant against QXO Inc.

UPDATE: Home Depot Pushes QXO Out of GMS Pursuit

Brad Jacobs, chairman and CEO of QXO, offers $5 billion to acquire GMS, a major distributor of gypsum and interior building products.

QXO Sets Its Sights on GMS in $5 Billion Offer

Undocumented workers make up 36% of the U.S. roofing workforce, leaving contractors and workers alike especially vulnerable.

Roofing is Left Exposed by Trump’s Deportation Flip-Flop

Roofing Contractor Webinar

Events

December 3, 2025

The Premier Roofing Conference: Best of Success

Join roofing professionals from across the nation at the 2025 Best of Success conference, the ultimate destination for roofing professionals seeking the latest industry insights and networking opportunities. Pick up strategies for critical challenges like workforce shortage with innovative solutions, explore the latest advancements in roofing technology and sustainable practices, and gain valuable insights from industry leaders on navigating the evolving roofing landscape.

View All Submit An Event
×

Be in the forefront of the roofing industry!

Join thousands of professionals today. Shouldn’t you know what they know?

JOIN NOW!
  • RESOURCES
    • Advertise
    • Contact Us
    • Directories
    • Store
    • Want More
  • SIGN UP TODAY
    • Create Account
    • eMagazine
    • eNewsletter
    • Customer Service
    • Manage Preferences
  • SERVICES
    • Marketing Services
    • Reprints
    • Market Research
    • List Rental
    • Survey/Respondent Access
  • STAY CONNECTED
    • LinkedIn
    • Facebook
    • Instagram
    • YouTube
    • X
  • PRIVACY
    • PRIVACY POLICY
    • TERMS & CONDITIONS
    • DO NOT SELL MY PERSONAL INFORMATION
    • PRIVACY REQUEST
    • ACCESSIBILITY

Copyright ©2025. All Rights Reserved BNP Media.

Design, CMS, Hosting & Web Development :: ePublishing