PURPOSE: To reduce the weight of a floor by a method wherein a rigid urethane foam layer in which a piping for a golf ball is buried is laid on a base board made of concrete and a leveling mortar layer is integrally laminated on the rigid urethane foam layer.

CONSTITUTION: A piping 14 for a golf ball consisting of a pipe made of a resin or a pipe made of a metal is arranged on a base board 10 made of concrete. A rigid urethane foam layer 11 is laid on the base board 10 made of concrete in a state that the piping 14 for a golf ball is buried therein. Further, a leveling mortar layer 12 is laminated on the rigid urethane foam layer 11 and a surface layer 13, such as a urethane sheet and an artificially lawn-shaped soft plastic sheet, is laminated for integral formation. This structure completely absorbs noise generated by the passage of the golf ball through the piping.