When the Cellynne Paper Corp. in Haines City, Fla., needed to upgrade its existing facilities to meet current FM Global insurance requirements, it turned to general contractor Alan Ulch Inc. in Winter Haven, Fla. As a Columbus, Miss.-based Ceco Building Systems builder, Alan Ulch Inc. had years of experience with metal building construction and had worked on the nearly 300,000 square feet (27,870 m2) of Ceco buildings at the Cellynne facility alone. Generally, these Ceco buildings were acceptable to FM with some minor alterations required for fire safety. However, a 410-foot- (125- m-) wide by 260-foot- (79-m-) long metal building constructed in 1983 needed a new roof system. Originally designed for 100-mph wind speed, FM was now requiring Cellynne to upgrade the existing roof to meet FM Global I-120 requirements.
MBCI, Houston, was contacted for its expertise in retrofitting existing building roofs. The project had all the usual issues and existing structural components that would have to be addressed for the new roof to become FM certified. The existing structural system had purlins spaced every 5 feet (1.5 m); the roof system was a trapezoidal standing seam with a floating stand-off clip; and the building’s width caused excessive thermal expansion. With these conditions, MBCI realized a new subpurlin framing system would have to be engineered.
The new system needed to satisfy the new roof’s field, edge and corner zone panel clip attachment due to the increased wind uplift requirements of FM Global I-120 mph. It also had to accommodate more than normal expansion and contraction because of the building’s 410-foot width.
Therefore, MBCI’s 18-inch- (457-mm-) wide, 22-gauge Double-Lok roof system’s clip attachment required a new subpurlin spacing of 5 feet in the field of the roof and edge zones and 2 1/2 feet (0.8 m) in the corner zones. MBCI designed a new zee purlin system to anchor to the existing purlins, leaving the existing roof in place. With the old roof having a major rib height of 3 inches (76 mm) plus, intermittent 6- by 12-inch- (152- by 305-mm-) long zee spacers were installed in the field of the roof at 4 feet (1.2 m) on-center directly to the existing purlins in the pan of the panel.
These spacers also accommodated the panel to be drawn down to a tight connection and allowed new roof plane alignment of the new purlins. At the edge zones, new 4-inch (102-mm) base zees were installed across the existing purlins spaced at 4 feet on center along each eave and up 25 feet (8 m) from the existing eaves. These base zees then received new 3 1/2-inch (89-mm) zee purlins attaching with a light-gauge flange-to-web clip. Typically, the edge zones would have required less than 5-foot purlin spacing, but because MBCI incorporated its Double-Lok wind reinforcement clamps, a 5-foot purlin spacing was sufficient. The thermal expansion and contraction was satisfied by using MBCI’s 4-inch Double-Lok sliding clip.
Instead of insulating between the old and new roofs, Alan Ulch Inc. elected to employ eave and ridge ventilation components to promote reduction in heat flow for above sheathing ventilation.
Ceco Building Systems
MBCI
