I know this type of question has been asked before but I am going to ask again since I couldn;t find it. The joists in the basment run 16 feet from wall to wall and are rough sawn 2X8 (they actually measure 2x8) so are sufficent for the supported span. Basically in order to address a sagging floor in my house I am going to install a support beam in the basement. So I was looking at making the beam with 2 2x10 with 3/4 osb or plywood in the middle and supporting with steel posts every 8 feet or so with 2'x2'x1' concrete and rebar footers. This sound about right?