How well did code-approved products perform during Ian?
Following Hurricane Ian, Intertek, a global provider of testing, inspection, and certification services, sent a large team to evaluate buildings after the storm.
By the early 2000s, many aspects of the first versions of the FBC had begun to take effect and the benefits were clear. Here are some of the key learnings:
Roofs
Roofs in high-velocity wind hurricanes represented one of the most challenging building components for engineers to tackle following Andrew, which was a Category 5 storm. Investigations after Andrew revealed the most damage was caused by building envelope failure due to blow-off of roof coverings, including the roof structure in many cases. Glass breakage and collapse of large doors were also primary contributors to building damage.
Ever since, roofing codes have gone through many refinements, as subsequent hurricanes were studied and laboratory testing of roofing products advanced. Roof attachment to the building, especially hip and ridge tiles, presented a challenge. These tiles were not adequately addressed by the code. Many roofers were still setting hip and ridge tiles on a bed of mortar, even where they had nailed or screwed the field tiles. Over time, the mortar’s grip on the hip and ridge tiles can weaken, leaving them without adequate attachment. The tiles would blow off and become airborne, essentially becoming small wind-driven missiles. This problem has been addressed using hip and ridge nailers attached these tiles, providing a more secure attachment method. Florida adopted the 2020 FBC, requiring a fully sealed roof deck, which will also help minimize interior damage from future hurricanes.
The roof-to-wall connection is also significant. A strong connection between the two is essential to prevent the roof from flying off the building, exposing its interior to significant water damage. Roof straps need to be fully wrapped around the roof trusses and wall structure. In addition, structures with continuous load path construction performed well. Tying the roof to the foundation with metal connectors and fasteners (such as straps, nails, and screws) means better resistance to high winds.
Intertek’s teams on the ground inspected hundreds of roofs and found those that were installed recently often performed extremely well. In addition to anchors, the use of adhesive foam instead of mortar was another impactful improvement. In general, metal roofs performed the best after Ian, but other newer roofing types and installation matters and newer roofs fared well.
According to Dr. Murray Morrison, managing director of research at IBHS, there is still room for improvement in the performance of asphalt shingles, the most common roof cover material. However, the performance of roofs now compared to 30 years ago is significantly better, thanks to improved materials, testing, and quality control (QC) codes. Many newer roofs installed in southwest Florida did not lose even a single shingle during the storm.
