Myer_-_Roofing_System_Warranty_AE_Recommendation.pdf

AE recommends Specification Section 07 53 23 EPDM ROOFING, Paragraph 1.8-A-1c read as follows:

“Warranty shall include roofing damage resulting from wind speeds up to and including 55 mph (3-second gust speed at 33 feet above ground for exposure category indicated) following UFC 3-110-03 Roofing, Section 2-2.7 in accordance with ASCE 7 uplift requirements.

NOTE TO DeCA PROJECT MANAGER

UFC 3-110-03 ROOFING is the governing criteria for roofing system design on military construction projects.

UFC 3-110-03 requires that wind resistance ratings for roofing systems be designed in accordance with ASCE-7 Minimum Design Loads for Buildings and other Structures.

It needs to be acknowledged that “Design Wind Speed” is different from “Design Wind Load Uplift Pressure” and “Design Wind Resistance Load”.

Calculations for the Fort Myer Commissary:

Design Wind Speed Design Wind Load Uplift Pressure Design Wind Resistance Load

90 MPH = 21.7 PSF in Zone 1 (roof field area), 43.3 PSF in Zone 1 (roof field area), 36.2PSF in Zone 2 (roof area perimeter) 72.4 PSF in Zone 2 (roof area perimeter)

54.6PSF in Zone 3 (roof area corners) 109.2 PSF in Zone 3 (roof area corners)

90 MPH design wind speed is the most common design wind speed throughout the United States and is the design wind speed at Fort Myer.

Building codes do not address warranty. Regardless of warranty requested, the roofing system must be designed for compliance with the building code, just like all other components of the building.

55 MPH and 72 MPH are the most common roof wind speed warranties. Warranties above 72 MPH will require special construction, such as concrete roof decks, etc.; that will significantly increase to cost of the building.

The Fort Belvoir project is nearby and requires a 55 MPH roof wind speed warranty.

To establish an acceptable comfort level, DeCA may elect to require a warranty of 72 MPH (just below hurricane level) or they may elect to require the industry standard 55 MPH wind speed warranty.

It should be noted that compliance with UFC 3-110-03 criteria, with 90 mil EPDM fully adhered membrane and cover board, will make it rather easy for the manufacturer to provide a 72 MPH wind speed warranty.

We had recommended a 72 MPH wind speed warranty on the Fort Belvoir project. It was decided that an industry standard 55 MPH warranty was sufficient.