Mastermech wrote:
Do you mean remove it all?? or just at the areas that are peeling.


No you don't have to remove anything that isn't loose.
Putting something over the loose part won't make it stick
tighter. So you need to lightly scrape all over to test for
looseness and where you find it scrape harder to remove the
loose paint. Then wash lightly and put undercoat on the
scraped areas to build those area up level with the
unscraped part and then put another coat on all of the
ceiling. Then paint normally.