I'm designing house plans for myself and I want to run a steel I-beam for the center support beam. The dimesions of the home is going to 32'x80' with a basement. Now my problem is; I'm not sure if I want to spread my floor joist 15'11" across(with a 16" spacing between rows) for my sub-flooring or run two support beams with my joist space at ~10'5". if I run the steel I-beam I'm definitly doubling up on the joist under the kitchen and the bath areas but what size joist should I use 2"x10" or 2"x8" and is it wise to have such a large spread between the poured wall and the center support beam. I think 2"x10" would be better since the floor joists would be spread so far apart need some help.