Knockdown plaster won’t adhere to ceiling in florida room. Flat roof. There’s no leak.Flaking occurs within a week or so in some areas. Have re-done affected patches several times & it recurs. Want to make ceiling plaster smooth (no more Knockdow). How do I do this?
Flat roof is building up heat and drying out the ceiling before it has a chance to cure. To remove the rest just wet it down and scrape off.
How long should it need to cure?
There's a chance you will have the same problem again after you redo it. I'd cover it with some type of wood, and that would also insulate it. Look over these ideas.
https://www.youtube.com/results?search_query=wood+on+ceiling
soak it and Scrape it off. it cannot be repaired........
Find out what the underlying problem is first and correct that so this doesn't happen again. Then scrape off the existing texture and retexture.
BTW: I lived in a house with a flat roof for 13 years, and never had a problem with my ceilings. I do not believe your problem is what William in Burbank, Il. said it is. Get a contractor if you cannot find the underlying problem yourself.
Popcorn ceiling don't last in high humidity areas. I live on the coast of NC and see this constantly, including in our offices. One issue is the ceiling has to be primed and sealed before applying the popcorn. But it will eventually blister and fall, regardless. Best option is to cover everything, goggles and mask, grab a scraper and get rid of it for good. Prime, seal, and paint for a smooth ceiling that won't be so ugly and frustrating.
This solution may work for you. You can ask someone at the hardware store if the Acryl Pro will work in your area, or contact Talissa (link in the post). Hope this helps. You will probably have to scrape off the knock down that is left on the ceiling to make sure you have a solid base for the ceiling tiles to adhere to. https://www.hometalk.com/diy/tile/ceiling/simple-fix-for-problem-ceiling-34327681?se=rep-20180115&slg=444d7c63f1adc6efd91a9e98c58be8a7-15958903&cid=5425326#c-5425326
I would scrape it off using warm water, messy, but worth it. Then use Kilz HighBuild if the drywall is scraped up to even it out, and then put a coat of paint on it.