A fastener driving tool and an adapter for a fastener driving tool are described herein for permitting accurate placement of fasteners with respect to an edge of a board (e.g., a top edge of a siding board). The adapter may include an adapter body having a central opening for receiving a head of a fastener driving tool and two or more pins positioned in the adapter body. At least two of the pins are positioned in the adapter body such that, when the central opening receives the head, the pins are equidistant from a center of a barrel through which the fastener driving tool drives fasteners.

A plurality of stacked fastener caps, each having a cap body. The cap body has first and second faces joined by a perimeter of the cap body, and adjacent faces of adjacent caps are joined by at least one connecting stem. The adjacent caps and connecting stems are integrally molded as a unit as by injection molding. One or both of the first and second faces may be planar. One of the first or second faces may be concave and the other may be convex. One or both of the first and second faces may have first and second thicker portions with a transverse groove interposed therebetween.

A roofing system, comprising an underlayment layer above a roof deck; at least one strap spaced horizontally up the slope of a roof deck and above the underlayment layer; at least two fasteners attached to the at least one strap and into the roof deck; at least one bead of adhesive applied above the at least one strap; and at least two metal roofing panels placed on the at least one bead of adhesive applied to the at least one strap.

A plurality of stacked fastener caps, each having a cap body. The cap body has first and second faces joined by a perimeter of the cap body, and adjacent faces of adjacent caps are joined by at least one connecting stem. The adjacent caps and connecting stems are integrally molded as a unit as by injection molding. One or both of the first and second faces may be planar. One of the first or second faces may be concave and the other may be convex. One or both of the first and second faces may have first and second thicker portions with a transverse groove interposed therebetween.

A roofing system, comprising: at least one strap spaced on centers horizontally up the slope of a roof deck; at least one bead of adhesive applied to the at least one strap; at least two metal roofing panels placed on the at least one bead of adhesive applied to the at least one strap; and at least two fasteners attached to the at least two metal roofing panels and into the roof deck at a top and perimeter of the at least two metal roofing panels.