Hi All! Had a little accident a few years ago while in tbe loft and put my foot through the ceiling to the room below. This ceiling was beautifully artexed. Anyway, patched it up from the room below (spare room) with a batten, but years later need to return this room to a living space, so got a plasterer to make good the damage - he put a couple of screws into the ceiling and that shored it up. Did a beautiful job skimming over the artex, but just before I was to paint the plaster, noticed that the plaster had cracked along the joint between 2 plaster boards right near where I'd put my foot through. The plasterer had taped the join and everything, but it had cracked along the seam anyway. I went up into the loft and removed the insulation, and there is a hardly discernible movement between the 2 boardsif I apply downwards pressure. So, I've been and marked out on tbe ceiling where the joists above run, and plan to screw some of those plasterboard screws into the ceiling, maybe 2 or 3 either side of the join onto the joists above, all the way across the room. Then hopefully get the ceiling reskimmed., as I guess it won't be possible to blend over the repairs. Anyway, question is:I've bought the special Phillips bits with cup, (after reading on this forum, thanks!) the plasterboard thickness is 15mm, should I just screw upto the skimmed surface, or should I remove the thin plaster around the screwhole and screw upto the plasterboard. ... also what screws are best for this repair job - too many on the Screwfix site to choose from!.... Or should I nail with large headed galvanised nails... the Screwfix ones don't seem to have a large head. Sorry its a bit long-winded but wanted to explain the back story.... Thanks!