22 CAR § 111-1207. Minimum roof slopes for positive roof drainage

(a) All state facilities of new construction shall be required to have roof surfaces with a minimum slope of one-quarter inch per foot (1/4”/ft.) for positive drainage. (b) Where possible, roof slopes shall be accomplished structurally in lieu of large amounts of tapered insulation fill to reduce costs and weight on the structural system. (c)(1) Avoid excessive slopes in excess of one-half inch per foot (1/2”/ft.) in built-up and modified bitumen roof assemblies which cause slippage and bitumen run-offs. (2) Use proper fasteners and bitumen for the slope of the roof and the type of roof assembly. (d)(1) On reroofing of existing facilities, the roof slope may be reduced to one-eighth inch per foot (1/8”/ft.). (2) The existing roof should be surveyed for areas which pond water. (3) These areas should be leveled or filled as required and practical for the type of substrate. (4) Verify that equipment curbs, counterflashing heights, and the like are of sufficient height for reflashing after the installation of new tapered insulation and roof membrane.