i am about to repair , or try to repair a hole in my plasterboard celing, but i am a little lost as to how i can do this. correct me if i am wrong but i was under the impression that when i cut back to the celling joists and place a new board in... it should lie back 2 or 3mm to allow for the finish to be applied .
But where i am missing the point or being just stupid if i put a 12.5mm new board to the allready 12.5 mm excisting board how is it going to lie back the 3mm needed to apply the finish as surley it will be flush.I know you can buy 9.5mm board but i was allways told for cellings it must be 12.5mm board anything less would crack .
please help
rnd