LAWRENCE BERKELEY NATIONAL LABORATORY, BUILDINGS 50 AND 78 ROOF REPAIR

Cerrudo was awarded the design build contract to perform roof repairs at Buildings 50 and 78. Building 78 is a 5,675 SF single story structure built into the north side of a hill. The existing roof is a concrete deck with a fully adhered built up roof and gravel cover. The roof repair for Building 78 was initially designed as a three-ply modified roof system based on the RFP requirements. The client requested a change of design to a PVC membrane roof system so that the existing built up roof could remain.

The existing loose gravel was removed. Tapered insulation was adhered to the roof, then DensDeck primed recovery board installed over the tapered insulation.  A Duro-Last PVC membrane roof system was adhered to the recovery board. The perimeter parapets were raised and new two-piece perimeter edge metal installed.

The new Building 50 roof over the existing library, 2,208 SF, was designed with a fully-adhered PVC membrane system. The existing built-up roof membrane was tested and found to contain PCB’s. The membrane was removed by workers trained in PCB removal and containment. A DensDeck cover board was installed over the concrete and corrugated metal roof deck, and rigid thermal insulation adhered over the cover board. A 40 mil PVC single ply white fully adhered field membrane with water-based adhesive was installed over the insulation, heat welded at laps. New gutters, downspouts and roof ladder were installed.