Double Roof System:
Retrofit Roof Saves Builder Time and Money
Capital Welding Inc. is a medium-size company that performs metal fabrication on structures and builds steel structures and stairways for a variety of customers. But after the roof on its 170,000-square-foot (15,793-m2) building began sprouting leaks, Capital Welding became a customer. The building at its Waldorf, Md., headquarters was constructed in three phases in the early 1970s. So the structure is actually three buildings joined by a large irregularly shaped common roof. But the 35-year-old roof had gone well beyond the stage of patching and caulking as witnessed by the numerous and widely scattered leaks.
To help solve the problem, owners Joe Bowling and Dave Hartley relied on the expertise of Joe Trossbach of Trossbach Enterprises LLC, Dameron, Md., a steel building erector. In 2004, Bowling and Harley had worked with Trossbach to construct a large ice rink and recreational facility in Waldorf.
Trossbach remembered reading about the Roof Hugger product and called on us for advice. To avoid interrupting Capital Welding’s business and opening the building to possible weather damage, we suggested retrofitting a new roof directly over the old one by using the engineering-certified Roof Hugger sub-purlin system.
Adding to the complexity of the situation was having two different roof slopes, one at 55,000 square feet (5,110 m2) at a 2:12 slope and one of 115,000 square feet (10,684 m2) at 4:12 slope joined by interior gutter. Trossbach determined the best way to deal with this interior gutter was to eliminate it and turn the building junction into a valley condition. Trossbach designed, fabricated and installed framing at the interior gutter areas to accommodate the new valley and adjust the two roof slopes, creating a clean, quick draining connection.
The rest of the project involved installing the retrofit system on the large roof. Using this type of system reduced the cost to the owner by at least 25 percent compared to the cost of using the old-fashioned method of tearing off and replacing the roof.
The new roof panels placed atop the retrofit system are thru-fastened Galvalume R style from Fabral, Lancaster, Pa. They are 12 inches (305 mm) on-center ribs made of 24-gauge high-tensile steel and installed over the old type 26-gauge R panel roof.
The project was completed in 2007. From start of design to completion required nearly five months, averaging over 10,000 square feet (929 m2) of completed roof per week, allowing for rainouts and holidays.
The owners of Capital Welding are now enjoying the several advantages of the new “double roof” system, as are their employees who no longer need to dodge the many leaks.
Dale Nelson is president of Roof Hugger Inc., Odessa, Fla.