Evening. Stud wall going in, unfortunately along the line of an RSJ. What would be the best approach? Ceiling will be having 25mm celotex below the joists - so would be possible to secure some ply to the joists to cover it then stud wall to that, perhaps. No fire requirements in this case (nothing above it).
Quickest way- gripfill or clear silicone the head plate and cut your studs tight. Won’t move once it’s cured.