A built-up roof over plywood sheathing on structural framing incorporates primary and overflow roof drain assemblies. The roof assembly includes two 2x8 minimum framing members at the sloped drain sump, a cant strip beyond, and framing blocking with 2x6 minimum members fastened with ten-penny nails at six inches on center staggered. A four-pound lead flashing sheet is set into roof cement over the installed base sheet. The overflow roof drain assembly features a shield positioned with its top two inches above the roof deck minimum and an exterior grade plywood backing of three-quarters of an inch. Dimensions establish a five-inch minimum clearance around the drain bowls and a twelve-inch separation between drains.
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