Gravel-stop perimeter flashing details for single-ply membrane applications differ from those designed for conventional multi-ply applications, as the membrane serves as the flashing material. The roof membrane extends over the perimeter edge and transgresses the fascia. The membrane should extend down the fascia a minimum of 1 inch below the outer edge of the roof deck. The membrane is secured to the fascia with fasteners and plates at a rate that is determined by wind-design zone requirements.
The flashing material is actually a stripping ply that is set over the perimeter gravel stop metal. The gravel stop should also be fastened in accordance with wind-design zone requirements. Typically a 6-inch flashing material is set over the metal and extends approximately 3 inches onto the roof membrane. The strip-in material should be applied in accordance with the membrane manufacturer’s requirements.
It is recommended that a separation sheet (or tape) be applied over the membrane and under the metal. The membrane and the metal have different coefficients of movement based on expansion and contraction.