Have Gyproc coving (larger format) Its been in place for over 15 years .... it was fitted as per specification with correct adhesive. On one room the length has a horizontal crack ... i.e along joint line with the ceiling. Still good on the vertical face so not come away form wall.
I assume I will scrape out the crack & widen it slightly, and then fill .... what would be the best filler to use ..... need it to re-affix to the ceiling board, not just fill.
Seen this stuff