Well since you have a structural stud wall supporting the 2 flitch beams and the joists are doubled around the main trimming area around the stairs, the overall joist spec looks fine as it is now.
Id be looking to see if any more of the stud walls below can be used to help strengthen the joists around the problematic area. You already have one structural stud wall, any more stud walls that could be used to help ?
You realise, that your screeded UFH will be adding a lot more load once its down ? This isnt going to help that area at all.
If you still have the floor acro'd, then I look at strengthening all the trimmers in that area and also look at any nailed connections direct applied to the joists. Studwalls, OSB, Hanger connections etc, these are all causes of squeaks.
Id be looking to see if any more of the stud walls below can be used to help strengthen the joists around the problematic area. You already have one structural stud wall, any more stud walls that could be used to help ?
You realise, that your screeded UFH will be adding a lot more load once its down ? This isnt going to help that area at all.
If you still have the floor acro'd, then I look at strengthening all the trimmers in that area and also look at any nailed connections direct applied to the joists. Studwalls, OSB, Hanger connections etc, these are all causes of squeaks.
