A band clamp used for forming a pipe lap joint. The band clamp includes a band, tightening mechanism, and gasket. The band extends circumferentially from a first end to a second end and is sized to fit over an outside pipe end. The tightening mechanism is connected to the band at the first and second end. The tightening mechanism includes at least one fastener to bring the first and second ends toward each other to tighten the band over the outside pipe end. The gasket is constructed to fit over an inside pipe end and within the outside pipe end such that the gasket is at least partially sandwiched between said inside and outside pipe ends. The gasket has an embossment extending radially outwardly from an outer surface of the gasket and being constructed to be received at least partly within a slot of the outside pipe end.