General Guidelines Alternate for Surface Mounted Counterflashing Scissors should always be used to cut the polyester fabric. Utility or razor knives tend to snag and tear rather than cut. Ply end laps should be four (4) inches (102mm) minimum with end laps for successive plies staggered no less than twenty-four (24) inches (610mm). Corner flaps should extend a minimum of eight (8) inches (203mm) past the corner with the ends of both plies, terminating on opposite parapet walls. The first ply of polyester should extend a minimum of four (4) inches (102mm) beyond the cant base onto the roofing membrane. The second flashing ply should extend an additional two (2) inches (51mm) beyond the edge of the first ply. Care should be taken not to cover weep holes. Drying/curing times noted are based upon good drying conditions. When conditions are other than these, e.g. high humidity, wet weather, etc., drying times may be longer. Wall coverings above the termination point of Koppers base flashing systems are not included in Koppers warranties. All metalwork, including counterflashing and coping, must be completed prior to acceptance for issuance of any Koppers warranty.  Return to Flashing Specification and Details