Show us your Roof
by Sharon Conners
RSI Magazine

Dri-Zone Inc., Laurel, MD took on a challenge in late 1999 to reroof 1,300 squares of roofing with Russell Williams Ltd of Odenton, MD - one of the worlds largest fabricators of metal, wood and plastic retail chain displays. Dri-Zone was referred to Russell William after it rented space in a 1,200 square warehouse that had to be reroofed in 1994. Dri-Zone installed a sprayed polyurethane foam (SPF) & gravel roofing system.

Through the years the owner had been struggling to maintain a ballasted EPDM system over lightweight gypsum poured panels (approx. 3' by 7') on his Odenton warehouse. Many (at least 30%) of these panels had become completely saturated as a result of poor maintenance over the years and some required replacement.

As might be guessed, the logistics of performing effectively under these circumstances was a long shot at best. With the full cooperation of Tom Harvey and others at Russell William, the contractor was able to make substantial headway during the mild Maryland winter.

Workers encountered not only wet gypsum panels, but saturated areas of BUR and modified bitumen roof systems. This job showed the virtues and flexibility of SPF, with its ability to add structural stability, seamlessly install slope to facilitate drainage and tie-into existing membranes of all types.

The owner supplied cut-to-fit CDX plywood (for the redecking) a bucket dumpster and the personnel to work the 'inside shop operation'. The CDX would allow a suitable substrate to spray the 2.8 pound density, structure enhancing, rigid polyurethane foam "back to-grade" prior to the application of a minimum of 1.5 inches of seamless, fully adhered SPF.

The toughest part of this job (as with any tear-off/deck replacement) was preparing for the unexpected thunderstorm. In this situation they would "fold back & save" a large sheet of EPDM membrane for emergency tie-in with SPF at the perimeters. Some days they replaced the deck, did a temporary tie-in and planned on installing membrane the next day- which worked out fine.

"We used the controlled environment of a 60-by-60 air-supported, heated tent during the cold winter months. When we reached the office area- we employed a Drywall type lift to keep the saturated panels from falling into the office area during the tear-out phase," said Ralph Chiodo, Dri-Zone Inc.

"All in all, it looks like the most important issues involved in performing a job of this scope are two fold, cooperation and imagination- the ability to think on your feet and create as the situation evolves," he said.