Abstract: A method of applying a roof membrane assembly to a roof deck. The method includes the steps of providing a roof membrane assembly including a first roof membrane and a second roof membrane. The first roof membrane has at least one longitudinally extending edge and the second roof membrane overlaps the first roof membrane and is bonded along at least one longitudinally extending edge of the first roof membrane to define a membrane flap having a longitudinally extending edge. The roof membrane assembly is then positioned upon the roof deck and at least one roof membrane fastening device is positioned over the first roof membrane and beneath the longitudinally extending membrane flap and secured through the first roof membrane and into the roof deck. The longitudinally extending edge of the membrane flap is then bonded to the first roof membrane.