Abstract: A fastener for securing built-up roofing membranes used to waterproof cementitious roof decks combines the conventional nail used for this purpose having a head and a shank portion designed to resist withdrawal of the fastener from the deck, with a non-integral tab penetrated by the shank of the nail and of larger diameter than the nail head, the tab having a design which allows the fluid asphalt conventionally poured over the nail during construction of the roofing membrane to bond the portion of the membrane beneath the tab and thereby increase the wind uplift resistance of the covering material. Removability of the tab allows its detachment in applications where increased uplift resistance is unnecessary.

Abstract: A sheet metal nail of the type used to fasten a first or covering material to a lightweight base material in which a pair of interfitted channel shaped leg or shank members are pivotally connected to the nail head in a manner to spread outwardly into the base material when the nail is driven therein. The penetrating ends of the shank members are tapered to form cutting edges so that as the nail is driven, the penetrating ends of the shank members cut through the first material without tearing such material.