Structural and Fire Performance

Codes Research
Contact: Gary Ehrlich
Director, Construction Codes & Standards
(202) 266-8545

Evaluation of Nailed Roof-to-Wall Connections for Resistance to Uplift. A report on a test program evaluating the uplift capacity of toe-nailed connections of roof trusses or rafter/ceiling joist assemblies to wall top plates. The results justify the 200-pound capacity for 3-16d nails used in the 2012 IRC and later editions as a trigger for hurricane clips, meaning roofs in low-wind areas are generally exempt unless roof spans are long or the house is constructed in open terrain (e.g. large lots in rural areas with few surrounding trees).

Evaluation of High Heel Truss-to-Wall Connections. A report on a test program to establish the lateral capacity of roof truss-to-wall top plate connections in the direction parallel to ridge and evaluate the use of wood structural panel sheathing in lieu of blocking. The results were used to justify a code change for the 2015 IRC to add an option to use the sheathing to provide lateral support in low-wind areas when high-heel (energy) trusses are used.

National Survey of Consumer Interest in Resiliency. Results from a survey of consumers to assess their perception of disaster risk and willingness to pay for more resilient construction. The results suggest a strong majority of consumers believe new homes built to modern building codes are more resilient than older homes and that most consumers are not willing to pay significantly more for increasing the resistance of new homes to natural hazards. There is some correlation between a greater perception of risk or higher household income and increased willingness to pay for more resilient construction.

National Survey of Home Builder Interest in Resiliency. Results from a survey of home builders to identify what “beyond code” construction practices they voluntarily use or would consider using and what, if any, mitigation incentives their projects qualify for. The results show most builders do not voluntarily implement beyond-code practices or have projects that qualify for incentives. Of those that do, practices to increase wind resistance tend to be the most popular; insurance discounts, FEMA grants and private retrofit grants are the most-used incentives.

Review of UL’s Study of Residential Attic Fire Mitigation Tactics and Exterior Fire Spread Hazards on Fire Fighter Safety. A technical review of concerns with the fire test parameters, specified construction materials and wall assembly details, and analysis of test results documented in a UL report intended to examine tactics for fighting attic fires. The UL report has been used in the code arena to limit the choice of, or require encapsulation of, certain wall materials, or to require fire-rated soffits. The technical review has helped combat these costly and limiting proposals.