Mclark

From my experience, 14" I-Joists 12" O.C. won't work on that span unless it's attic space or something. On a wide open floor with no bearing walls or roof bracing on this joist in the span, It would take like a 3.5" flanged 16" I-joist 12" O.C. If your foundation isn't a basement, I'd put a girder with piers through there like a crawlspace. Then you could use 11-7/8" I-Joists 16" O.C. if there's no load bearing walls on the joists. I'm no engineer but this should work.