Hidden fastener unit and related method of use

A fastener unit adapted to secure at least one board to a support, the fastener unit comprising:

• a spacer block intersected by a grip element integrally formed with the spacer block to form a monolithic polymeric piece, the grip element projecting from the spacer block in a cantilevered manner, the grip element configured to fit in a first groove defined by a first board, the monolithic polymeric piece extending from an upper surface to a lower surface of the spacer block;
• a fastener extending through the spacer block and the grip element from the upper surface to the lower surface of the spacer block, the fastener extending along a vertical axis of the spacer block, the fastener disposed between a front surface of the spacer block and a rear surface of the spacer block, which define a thickness therebetween, the thickness corresponding to a preselected gap between the first board and a second adjacent board, and
• a first wing extending away from the spacer block and adapted to fit within and contact the first groove and to thereby secure the spacer block adjacent the first groove and establish the preselected gap between the first board and the second adjacent board,
• wherein the spacer block surrounds the fastener from the upper surface to the lower surface such that the fastener is concealed in the spacer block from the grip element to the lower surface;
• wherein the first wing terminates at a first tip and comprises an elongated arm comprising:
• a proximal end joined with at least one of the grip element and the spacer block;
• and
• a distal end comprising the first tip,
• wherein the elongated arm longitudinally extends alongside a side surface of at least one of the grip element and the spacer block parallel to a plane containing the vertical axis such that the distal end of the elongated arm is opposite the proximal end across the vertical axis.