The size of timber sills (sole boards) or laminate type shall be at least 225 mm (9") wide with a minimum thickness of 38-44 millimeters (1.5"- 1.75") to spread the load under base plates on the supporting surface. The ground beneath sills shall be level and compact. A sill shall extend under at least two standards unless the uneven surface or ground prevents it. In cases of uneven surfaces, individual sills under each standard shall be at least 765 mm (30") long.