A thick mat 25 is laid on the floor subbase 4 having the low upper surface, the thin flooring 5 is laid on the high floor subbase 4', and both upper surfaces are flush with each other. 高さの低い床下地4に厚さの厚い畳25を敷設し、高さの高い床下地4′に厚さの薄いフローリング材5を敷設し、それぞれの上面を面一とする。 - 特許庁