A composite board for use as backerboard for tile includes outer reinforcement portions and a polystyrene layer disposed between the two outer reinforcement portions, at least one of the outer reinforcement portions being an outer mat fabric reinforcement layer with a mat fabric, and a non-shrinking cement compound saturating and connecting the two outer portions with the polystyrene substrate. A method of installing a composite tile backerboard involves placing the composite board against a fixture protruding from a flat surface, pressing the composite board against the fixture to emboss the features of the fixture on the surface of the composite board, and cutting a hole in the composite board based upon the features of the fixture embossed on the composite board.