Projects

Retrofit

Wind Uplift Capacity of Foam-Retrofitted Roof Sheathing Subjected to Water Leaks
Failure of roof sheathing during extreme wind events is a common failure mode in residential roofs. The majority of hurricane-related losses are sustained by residential homes and 95% of these are from failures within roof-systems (Baskaran, Dutt, 1997). Inadequate fastening of wood sheathing to roof framing members is the most common failure mode. Roof sheathing failure causes major losses for two primary reasons: (1) the loss of diaphragm action weakens the lateral stability of the roof, leading to roof failure and progressive collapse of the building; and (2) openings made in the roof can allow water to intrude which severely damages interior components and building contents. Despite enhanced building code provisions that have improved the construction of newer homes, over 80% of the existing residential housing stock in these hurricane-prone regions were built before any building code changes (Datin, Prevatt et al., 2011). Thus, a significant portion of the existing housing stock remains vulnerable to these damages. Therefore it is beneficial to identify viable retrofit options to improve the uplift capacity of these vulnerable roof systems.

David O. Prevatt, Kenton McBride, David B. Roueche, and Forrest J. Masters, “Wind Uplift Capacity of Foam-Retrofitted Roof Sheathing Subjected to Water Leaks,” ATC-SEI, Miami, Fl, 2012, pp. 305-306.

Modular Green Roofs

High Speed Wind Uplift Research on Green Roof Assemblies

The purpose of this research project was to develop wind resistance tests and to evaluate the characteristic response of green roof systems to extreme winds. The two-year study
investigated two types of green roof systems; modular tray green roofs and built-in-place green roof systems.

Tuan D. Vo, David O. Prevatt, G.A. Acomb, N.K. Schild, and K.T. Fischer, “High Speed Wind Uplift Research on Green Roof Assemblies,” Cities Alive, Chicago, IL, 2012, pp. 1-11

Nail Withdrawal

Effects of Installation Method on Nail Withdrawal Capacities
Sheathing attachment is extremely important in residential structures. The roof is usually the first thing to fail in a windstorm and once this happens the remaining structure is more unstable. Wood residential buildings account for 60% of all damages in wind storms (Sparks, 1991) and 95% of residential economic losses are from failures associated with the roof (Baskaran, 1997). These failures are due in part to inadequate strength in fasteners (primarily nails) attaching wood sheathing to the wood rafter (Shreyans, 2012). The objective of this current study is to evaluate the effect of the nail installation method on the nail withdrawal capacity.

Ashlie Kerr, Shelly Dean, and David O. Prevatt (2012). Effects of installation method on nail withdrawal capacities. Manuscript submitted for publication, Engineering School of Sustainable Infrastructure and Environment, University of Florida, Gainesville, FL.

Shingles