Many customers who we’ve installed crown moulding for, have “Popcorn(stipple)”, or “California” ceilings in their homes. Once the crown is installed, caulking fills the gaps between crown/wall/ceiling so that it looks seamless, and great! No preparation needs to be done prior to the crown being installed.
One benefit to installing crown in this situation is that it provides a laser-straight line where the bottom of the crown meets the wall.
Click on photo below.
Happy Renovating!