The IRC specifies minimum requirements for continuous roof sheathing at gable end walls, including fastener (nail) type, spacing, and penetration depth into structural members. Confirm with the local building department if the house is in a hurricane-prone region and if local requirements exceed those of the IRC. The IRC defines Hurricane-Prone Regions as areas along the Atlantic and Gulf Coasts where wind velocity is >115 mph, and Hawaii, Puerto Rico, Guam, the Virgin Islands, and American Samoa (see the IRC wind map in the Climate tab). Homes located in coastal high-wind areas including Hurricane-Prone Regions generally require enhanced attachment that can withstand greater wind speeds than the rest of the country. For some high-wind regions, the IRC requires wind design in accordance with other methods including the International Building Code (IBC). The International Residential Code (IRC) requires exterior building components and their attachments to be capable of resisting design wind-pressures. (Source: FEMA 1992.)įigure 3. Connection Points for Gable End Overhang with Outriggers. (Source: Gable End Overhangs.)įigure 2. Gable end roof overhang framing with outriggers for resistance to high winds. Figure 1. Wind uplift pressure forces acting on a gable end overhang with ladder framing. Outriggers, which may be 2x4 members or 2圆 members, are then installed on top of the gable truss or rafter so that they butt up against the truss or rafter next to the gable truss and extend outwards to support a fascia board along the edge of the overhang. The size of the gable truss or rafter or truss is adjusted such that the top level of the end truss or rafter is less than the top level of the rest of the trusses or rafters to provide enough space for the outriggers to pass above the end rafter or truss. Outrigger framing is typically used for overhangs greater than 12 inches. Ladder framing is typically limited to shorter overhangs of 8 to 12 inches. Roof sheathing is installed above the overhang and provides structural support and resistance to wind uplift. This framing is attached by nailing through the gable wall sheathing into the last truss or rafter. Ladder framing is constructed using two long parallel boards that are connected by short blocks, like the rungs of a ladder. New construction and roof retrofits are opportunities to upgrade the gable roof overhang to meet standards and building codes and to decide if selecting an above-code strategy for an added level of protection is the right choice for the project. Two common methods of framing gable roof overhangs are ladder framing and outrigger framing. The exposed roof can allow rainwater to enter the building, causing severe damage including saturation of insulation and ceiling drywall, potentially leading to collapsed ceilings and extensive damage to interior finishes and household contents. Although an important structure of the house, it is also one of the most vulnerable components during high-wind events.ĭuring a hurricane, tornado, or high winds, gable roof overhangs are subject to significant uplift pressures (Figure 1) and can be damaged or blown off, leading to severe damage to the roof and other structural members of the house. It also protects doors and entryways, provides shade to windows, and protects the foundation from excess water runoff, which helps to keep the basement and crawlspace dry. The gable roof overhang reduces the amount of rain that hits the exterior of the home, thus providing additional protection from water damage. Gable roof overhangs provide shading and protection from the elements and can also be considered desirable aesthetically. See the Compliance Tab for related codes and standards requirements, and criteria to meet national programs such as DOE’s Zero Energy Ready Home program, ENERGY STAR Certified Homes, and Indoor airPLUS. Install a rigid soffit material such as structural sheathing plywood or OSB to cover the underside of the overhang.
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