![]() ![]() The roof decking to roof rafter/truss connection strength can be doubled without replacing the roof covering by applying a two-part, spray polyurethane foam adhesive to the underside of the roof deck as shown in Figure 1 (ASC 2008). Retrofit Strengthening of the Roof Decking to Rafter/Truss Connection without Roof Cover Replacement Using High-Density Spray Adhesive The last point is covered in-depth in a separate Solution Center guide, Bracing of Roofs for Hurricane, High Wind, and Seismic Resistance. ![]() Retrofit bracing and strengthening a roof consists of strengthening the connections of the roof decking to the rafters or trusses,, the rafters/trusses to the top plate, and the wall studs to the top and bottom plates, and increasing the shear strength of the wall. Additionally, insurance companies sometimes provide significant financial incentives to homeowners to perform such retrofit strengthening work. Fortunately, an arsenal of retrofit solutions exists for strengthening existing homes. Older, unreinforced homes can incur extensive damage when subjected to high winds or a seismic event, threatening the safety and security of the occupants. These older homes are likely to lack the metal connectors that make a home far more resistant to uplift forces during high winds or the necessary braced wall paneling to resist shear forces during an earthquake. However, older homes built to the weaker building codes of the past are at risk. Today’s building codes already incorporate stringent requirements to help protect new homes from catastrophic failures during high winds, hurricanes, or seismic events. 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 Single-Family New Homes, and Indoor airPLUS. Department of Energy’s Standard Work Specifications (SWS) for more on installing spray polyurethane foam in unvented attics. Pre-Retrofit Assessment of Hazardous Materials.Pre-Retrofit Assessment of Attics, Ceilings, and Roofs.See the following Building America Solution Center guides for more information: ![]() Or, provide coverings for non-impact-resistant skylights and windows. Install skylights and windows with impact-resistant glass in regions that experience high winds and hurricanes.Install structural screws or metal straps to connect the roof and wall top plate framing to increase the strength of the roof trusses or rafters against uplift.Install a two-part spray-applied polyurethane foam adhesive to the underside of the roof to increase the uplift strength and rigidity between the roof sheathing and the trusses or rafters.To retrofit the roof of an existing home for high-wind or seismic resistance: ![]()
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