Loft conversion floor

[Deluks]

If I had a loft conversion done, what type of flooring would be suitable on the joists, are there regulations dictating the type of material that has to be used?
The room would only be used for storage/work, but I'd be up there quite a bit so the proper structural floor job is neccesary.

I would've thought pine floorboards would be the norm, but is it possible to save some cash and use standard sheet materials like 8x4 ply, OSB etc

 

[masona]

OSB is not acceptable for flooring, it's mainly for shed floor or roof. T&G chipboards, T&G flooring or plywood is acceptable but check with BCO first.