Roofing cover board, roofing panel composite, and method

A prefabricated roofing system panel comprising:

• a cover board;
• the cover board comprising a high-density predominantly polymer material core layer, the high-density core layer of the cover board having a density between 6 lbs/ft3 and 25 lbs/ft3 and a thickness of about 0.08 inches or greater;
• the high-density core layer of the cover board having a length, a width, and a thickness;
• the high density core layer of the cover board having a top major surface and a bottom major surface that are each defined by the length and the width of the high density core layer,
• an insulation board, the insulation board comprising a low-density predominantly polymer material foam core layer;
• the low-density foam core layer of the insulation board having a density less than 6 lbs/ft3 and a thickness of about 0.50 inches or greater;
• the low-density foam core layer of the insulation board having a length, a width, and a thickness;
• the low-density foam core layer of the insulation board having a top major surface and a bottom major surface that are each defined by the length and the width of the low-density foam core layer;
• the bottom major surface of the high-density core layer of the cover board and the top major surface of the low-density foam core layer of the insulation board being substantially coextensive;
• and
• the cover board and the insulation board have a common nonwoven mat facer that overlies and is bonded to the bottom major surface of the high-density core layer of the cover board and the top major surface of the low-density foam core layer of the insulation board to bond the cover board and the insulation board together;
• wherein the cover board includes a top facer overlying and bonded to the top major surface of the high-density predominately polymer material core layer, and the top facer comprises a nonwoven mat.