Washer and combination washer and fastener system for building construction

A washer for use in building construction, said washer comprising:

• an outer side having an upper surface defined by an upper wall, an underside opposite said outer side, and a perimeter;
• a central aperture extending from said outer side to said underside;
• an engagement portion configured to be a projection member, wherein said projection member extends upward from said upper surface, said engagement portion configured for selectively mating with an adapter of a fastener gun for locating the fastener gun relative to said central aperture;
• a receptacle, said receptacle being disposed inwardly of said projection member, with said central aperture forming an opening in said receptacle;
• a central chamfer disposed at said central aperture, said central chamfer configured to mate with the head of a fastener driven by the fastener gun;
• wherein said upper surface of said outer side comprises a conical portion extending from said perimeter to said projection member, and wherein said engagement portion includes a top surface with said receptacle being recessed relative to said top surface.