A textured ceiling, sometimes called a “popcorn” ceiling, can be very difficult to paint. The minute you start rolling it, pieces of the texture start falling off.
The key to a successful paint job is to use a slightly thicker nap roller cover, at least 1/2″ thick, and roll a light coat on the ceiling in only one direction. Don’t roll back and forth. Slightly overlap the next row, rolling it in the one direction.
Allow this light coat to dry, then apply a second coat of paint, but roll perpendicular to the first coat. Some flaking of the texture will still occur, but it will be very minimal.
This technique will take a little longer, but it practically guarantees a beautiful paint job overhead without a floor full of popcorn when the job is all done.