Patent ID: 8104248

Claim:
A method of fastening a cover board to a support comprising: providing the cover board having a support face and an opposing exterior face; providing a plurality of substantially identical plugs, said plugs and cover board having substantially the same material composition, said plugs having an upper enlarged cylindrical portion and a lower reduced cylindrical portion with a tapered transition portion between said upper enlarged cylindrical portion and said lower reduced cylindrical portion; disposing the cover board on the support so that the support face is adjacent the support; providing a plurality of fasteners each having a threaded shank extending from a head; driving each fastener threaded shank through the cover board and partially into the support at a pre-established depth; forming a cylindrical counterbore in the cover board above the head at the same time each fastener is being driven through the cover board; and disposing a plug having a substantially planar exterior face in each counterbore so that the exterior face of said cover board and said exterior face of said plug are co-planar, and said upper enlarged cylindrical portion of said plug engages said counter bore and said lower reduced cylindrical portion is spaced from said counter bore to form an annular cavity.