Our home is 13 yrs. old its a ranch style home, with 9 1/2" x 16' laminated floor beams that are set 2' apart on center. This is where the probelm is. This span is to great so I need to either buy some more laminated beams (same size) and set then between the ones I have now at 12" on center but I don't know if I can get them inbetween the floor and the main support beam. or another idea is to buy some 7/16 OSB and rip them to 9 1/2"x8' and glue and screw them to the face of the beams I have now. what does anyone think of those ideas?

The original builder overspanned this for sure. There are several ways to solve it, one of which is as you suggest. The addition of ripped Osb would not be a good solution.

One start would be to take your information to the lumberyard where you will buy the new material. They have software to facilitate the sale of engineered wood joists they can use to suggest how it should have been built. Then you can plan have to get from A to Z

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