A prefabricated, faced roofing board composite includes a first board layer made of a polymeric material or a predominantly polymeric material and a fire and weather resistant fiberglass-based facer bonded to a top major surface of the first board layer and forming a top major surface of the composite. The fiberglass-based facer is substantially impervious to the passage of hot gases of combustion, water, and water vapor through the thickness of the fiberglass-based facer. The faced composite can be a cover board, an insulation board; can include cover board and insulation board layers; and can include cover board, insulation board, and baseboard layers. A second fiberglass-based facer that is substantially impervious to the passage of hot gases of combustion through its thickness can form a bottom major surface of the composite. The polymeric material or predominantly polymeric material of the board layer to which each fiberglass-based facer is bonded penetrates part of the way through, but not completely through, the fiberglass-based facer.