I keep getting a crack appearing in my ceiling, it is a plasterboard ceiling which I believe has been skimmed (I’m not in the building trade). I have used all types of crick filler from the DIY shops. Allowed it to set for longer than stated then I have sanded it only for the crick to reappear a few days/weeks later. My last attempt I made the crick wider and smoothed the sides only for my wife to spot that the crack was back a few weeks later. It is driving me mad!! Can anyone help!