My husband and I are trying to find the best way to paint over ceilings that already had sand paint on it. Not very heavy sand but we have had to do some spackling over quite a few nails and that created smooth area's. We had to prime the ceiling first because there were water stains from an old roof leak. We just attempted one room with new premixed sand paint and it was very labor intensive and messy! We were advised to use a loop roller and it was terrible. A very heavy texture. We tried a roller and it wouldn't load the paint. My husband finally used a very course brush that he used for sand paint once before. It took 3 1/2 hours to paint a 10x12 room. We have four other rooms with the same issue. Any advise would be helpful.

The site in the link below has some great advice, search it well and you may find far more answers then you had hoped for..

http://www.drywallschool.com/textures.htm