Why Pine City is differentWhat did the July 2019 hail do to a Pine City flat roof?
On July 19, 2019, NOAA storm reports put 2.75-inch hail near Pine City. The next day we walked the flat roof at Eide Chrysler Dodge Jeep Ram and photographed what a big rubber roof looks like after a storm like that: standing water across wide areas, split seams at inside corners, a torn section of membrane, and a lifted piece of metal coping at the roof edge.
Big commercial roofs along I-35 in Pine City are mostly flat or low-slope, covered in black rubber membrane with metal coping at the edges and rooftop units, exhaust fans and satellite dishes on top. Hail doesn't dent a membrane the way it dents a car. It bruises and cracks it, and the damage hides under standing water until someone walks the roof and feels for it.
That's what our July 20, 2019 photos show at the dealership. Rainwater was still sitting in the low areas and along the parapets. The inside corners, where the membrane folds up the wall, had split seams we could get a finger into. One section of membrane was torn open, and a length of metal coping at the roof edge had lifted off. We photographed the rooftop units, exhaust fans and the satellite dishes sitting in water, so the owner had a full record of the roof the day after the storm.
Pine City has a long history with roofs and storms. In 1952, lightning struck the 1886 Pine County Courthouse, a towered Romanesque Revival building, and destroyed it. Today's storms are more likely to be hail and straight-line wind, and a flat roof that ponds water gives both more to work with. We check drains, seams, corners and edges first.