OK this may be a silly question but given a typical 7"x2" floor joist with a span <10'0" and a typical floor board (3/4" Pine) what will the SWL be? joists on 16" centres ,area of floor 242 sq ft (22'0" long x 11'0" wide) mounted on 2'x2'x2' foot cube concrete footings x 8 ground base is London clay?????????? please help,,thanks Tony.