Building a loft in an old barn

[Suje]

I have a vacation home with an associated barn measuring 32.2 sqm where I plan to utilize the ceiling height and build a loft over half the barn to increase storage space.

The barn measures 5.2m*6.2 and I envision a construction where I use joist hangers and attach the beams on the long side and frame up so I can "lay" a floor. The joists should then be about 5 m without support from below.

Does anyone know how I calculate both the dimension of the joists that should support the floor and how closely I should set the joists?

Suss

 

[Oldboy]

5m is a long span. It will be glulam beams. I can't answer the dimension. I don't know if, for example, Svenskt trä has any calculation function that covers this.