The way we protect our building from the weather depends on where it is located. Here is Florida, our eyes are focused on the ocean. With the 2010 Hurricane Season now in full swing, and the impact of Hurricanes Ivan, Andrew, Katrina and Rita are not easily forgotten.Walt Rossiter, of the National Hurricane Center, describes a school building he investigated in southern Florida following hurricane Andrew. “The school was of masonry construction and built like a fortress,” he said. “It was built around an interior courtyard, and most of the building’s windows faced this courtyard — there were very few on the exterior walls. But the roof ended up in the parking lot. I believe that, if the roof had stayed on the building, the school would have passed the storm largely unscathed.” Rossiter’s story highlights a crucial fact about roofing performance during big storms: A roof system’s ability to withstand gale-force winds often determines how well the rest of the facility survives.
What Can Go Wrong?
Imagine a hurricane has hit and now the facility’s roof is in the parking lot. What caused it to fail? Typically, there is no quick answer. There are as many ways for roofs to fail as there are roofing systems. But when roofing systems fail, they usually do so at areas most susceptible to uplift: the perimeter, corners, along seams, and at rooftop accessories, such as vents, satellite dishes, or A/C units. Rossiter says that weak areas of attachment are the leading cause of roof damage. “Recently, a high wind event we investigated revealed damage and failure due to a gutter edge,” he says. “The gutter and components above it were blown back onto the roof along with four feet of roofing at the edge.” Even though the gutter was attached properly to the wood blocking, the blocking attached to the structure itself had failed. Further investigation revealed that the blocking had been attached at spacing greater than 12 inches using nails. “The blocking was most likely installed by another trade and not confirmed to be attached to meet the same uplift resistance as the roof, roof edge and gutter,” Rossiter says. The good news for the affected facility was that a perimeter attachment strip of the roofing system stopped the wind damage from migrating further than four feet from the gutter edge.
If A Hurricane Hits
The perfect storm is coming and you did not get a roof inspection or prepare. Now what? “You pray,” says Rossiter. All joking aside, a roof should be adequately secured well ahead of a hurricane’s arrival. Nevertheless, some last-minute checks should be made on the rooftop. Act before hurricane season, because vital resources often become scarce. Also before hurricane season, call RAMCON to get a roof inspection. They provide a detailed inspection and report that covers all the bases. Roof defects should be repaired, and all rooftop equipment should be reviewed to ensure there are no loose parts. Make sure that the equipment is functioning properly and well attached to the structure. In particular, you should physically check equipment screens, access doors, exhaust fans and roof drainage components. Make sure that removable panels are tightly secured to equipment. Clear paths and drainage so as not to impede water flow. Loose or compromised material should be taken off the roof. As much as possible, you should review the area surrounding the building. If you see a dead tree limb or a loose sign near your roof or on a neighboring building, remove those windblown hazards before the storm season approaches.
Taking corrective action now can reduce a facility’s susceptibility to storms — and protect the roofing system when a hurricane arrives.
