Roof drains and overflow drains are installed over roof sheathing with a minimum 2-foot separation and tapered rigid insulation at the drain sump. A single-ply roof membrane runs continuously over the rigid insulation and is sealed at the drain flange with reinforced membrane and sealant. An overflow drain includes a 2-inch collar matching the required sump slope of less than 3 inches to 1 horizontal foot. All components are installed strictly per the manufacturer recommendations.
ROOF SHEATHING, SEE STRUCTURAL FOR DRAINS WITH TAPERED RIGID INSULATION OR EQUAL AT DRAIN SUMP LESS THAN 3 INCHES TO 1 HORIZONTAL FOOT ROOF DRAIN, INSTALL PER MANUFACTURER SEALANT REINFORCED MEMBRANE RIGID INSULATION A542 8 2'-0" MIN. 2" OVERFLOW DRAIN TAPPER INSUL TO COLLAR 2" COLLAR @ OVERFLOW DRAINS ONLY ROOF DRAIN RIGID INSULATION SINGLE PLY ROOF MEMBRANE OVER RIGID INSULATION ROOF SHEATHING (SEE STRUCT.)
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