A roofing system includes a construction board positioned over a roof deck and a plurality of fastening plates positioned on a top surface of the construction board. At least one connector extends between two of the plurality of fastening plates and is positioned on the top surface of the construction board. The construction boards may be insulation or cover boards, and in certain embodiments may be polyisocyanurate boards. Fasteners are driven through the fastening plates and the construction boards and into an underlying roof deck to secure the construction boards in place.