MOTT FOUNDATION BUILDING

Office Building in Flint, Michigan

Project Size: 36,000 square feet, split between two levels (upper 11,000; lower 15,000)
Project Type: Recover and ballasted
Roof System: 40-mil custom prefabricated PVC membrane manufactured by Duro-Last.
Other Details: The Charles Stewart Mott Foundation Building is a historic structure in Flint, opened in 1930. The roof has two main levels, with some raised sections on the lower level.

The upper level has an elevation of 216 feet above the street. The client wanted to re-use the stone ballast that was in place over the existing EPDM membrane, so Versatile had to move all the stone to one side of the roof and install the new Duro-Last 50-mil membrane over the now-exposed roof surface. Versatile then moved all the stone to the new membrane section, installed the remainder of the Duro-Last roof, and finally spread the ballast evenly over the entire surface of the new roof. Versatile also installed walkpads on the upper roof level.

On the lower level, Versatile recovered the existing EPDM roof with a layer of half-inch fanfold insulation and a mechanically attached 40-mil Duro-Last prefabricated system.

The owners required that the building’s original stonework façade be preserved “as is.” So rather than edge the outside perimeter of the building with metal, Versatile terminated the roof membrane on the vertical surface of the interior of the parapet wall.