Loft floor separating from joists

[Ted Phillips]

Hi

Used loft stilts in loft to maximise storage while maintaining adequate insulation. No probs for years, then noticed slight crack in landing ceiling. Investigated and found an area directly above where there was a gap between floor and joist.

Spike to builder friend who advised fixing 50mm dry lining screws to secure. Have done that, concentrating on most affected area, with view to repair and paint afterwards.

Have two queries:

1. Have I gone OTT with three screws covering that area?
2. Re cause if problem. We had been guilty of overloading boards, but curious why weight would cause this separation? Wouldn’t that normally push joist down with board?

Thanks