Roofing Code: Roof Assemblies
IBC 2012 Section 1504.1, Wind Resistance of Roofs
Roof decks and roof coverings shall be designed for wind loads in accordance with Chapter 16 and Sections 1504.2, 1504.3 and 1504.4.
This section implies that wind-engineering calculations should be completed for all roofs. Section 1603.1.4, “Wind Design Data,” states, “The following information related to wind loads shall be shown, regardless of whether wind loads govern the design of the lateral-force resisting system of the structure.” Wind design calculations should be completed in accordance with FM or ANSI and shall include the following criteria:
- Ultimate design wind speed (3-second gust), miles per hour (km/hr) and nominal design wind speed, as determined in accordance with Section 1609.3.1.
- Risk category.
- Wind exposure; applicable wind direction if more than one wind exposure is utilized.
- Applicable internal pressure coefficient.
- Design wind pressures to be used for the design of exterior component and cladding materials not specifically designed by the registered design professional responsible for the design of the structure, psf (kN/m2).
This section also implies that each roof covering — clay and concrete tiles, as well as mechanically attached, adhered and ballasted low-slope systems — should be applied in accordance with attachment methods for localized wind requirements.