A Tale of Two Roofs

On August 12, 2010 around 1:30 pm a summer storm swept through the St. Peters, Missouri area. It has not been determined if it was straight line winds in excess of 100 mph or a tornado that hit The Plaza at 94 strip center owned by Corporate Group.
The Plaza is made up of three buildings. The building farthest to the north was hit the hardest. The roof had a firewall separating a 4-ply built up roof system from a Sprayed Polyurethane Foam (SPF) roof system. On the west side of the firewall was the 4-ply built-up roof and to the east was the SPF roof. The 4-ply built-up roof was between 12-14 years old. The SPF roof was 12 years old and installed by R&A Contracting.
R&A Contracting re-coated the SPF roof a month before the storm and its new 10-year warranty for the SPF section of the roof went into effect. When the storm hit, it destroyed the 4-ply built up roof. The 4-ply roof was torn off all the way down to the metal decking, strewn all over the parking lot, and in some cases, pieces were found over two blocks away.
The SPF roof system remained intact and fully adhered to the metal deck. A small HVAC unit was literally ripped out of the roof and dropped further down the roof, causing damage to the SPF roof. There was other minor damage to the SPF roof from debris and the 4-ply built-up roof that landed on top of the SPF roof as it was being ripped off the metal decking by the storm. The SPF roof even remained waterproof despite the punctures in the SPF roof system from flying debris.