I want to spray a ceiling to seal it and possibly also obscure the uneven surface but am unsure what will stick well. This ceiling assumably used to have tiles. There is an array of thick glue-like blobs over drywall. I believe this mastic could be unsafe to leave exposed and unsafe to scrape or sand, in addition to being a lot of work. I have an airless paint sprayer and can rent a large texture sprayer for cheap. The question is, what will adhere to this ceiling and not fall off? Can I spray drywall mud, then primer, then knockdown texture, then latex paint? Are there special products that might bond better than the drywall mud?

  • If the mastic bumps are thick it might be better to trowel the mud , I am not sure why you think mastic would be unsafe to scrape. It may be liquid nails or another construction adhesive.
    – Ed Beal
    Nov 9, 2018 at 20:39
  • Up until the 1980s, manufacturers mixed asbestos into many types of mastics. These old ceiling tile glue pods might be unsafe and I wish to entomb then rather than disturb them.
    – thorr18
    Nov 10, 2018 at 0:48
  • Asbestos was used in almost all popcorn ceilings but I do not remember it being in products other than black mastic that stuff is full of it.
    – Ed Beal
    Nov 10, 2018 at 17:29

1 Answer 1


Acrylic admix is a liquid additive formulated to increase bonding performance when mixed with joint compounds or texture when additional adhesion may be required or when applying over questionable surfaces. It seems to work for this purpose.

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