Can I mud over ceiling tiles?

I have a 1/4 bath (vanity only) that has a ceiling made of 12" square tile which are basically thick paper/cardboard that has been painted. I shaved a sample off the edge and submitted it for asbestos testing, which came back negative and described them as 87% cellulose. I think these are glued onto the ceiling.

There are hairline cracks between them. Would priming/sealing the surface with Gardz, then skimming it with a couple of coats of lightweight hot mud be any better at resisting cracks than just a couple of coats of a good latex paint?

 

Welcome to the forums.

In my opinion you'd be better off removing those tiles.
The weight of the mud pulling down on them and with them flexing your mud is going to crack.

 

Ya, while you could mud over them I wouldn't expect it would look good for long.
I agree with replacing it with drywall. Short of that you could caulk the seams and then repaint the ceiling.

 

Those tiles are always subject to cracking. When originally installed there were visible seams between them and that was the look. If they've been painted however it can seal over the seams but then as the cellulose absorbs or looses moisture with the humidity in the house they expand and contract and eventually the paint cracks. This is also why they aren't a good base for any type of mud as they are always expanding and contracting.

If you want a smooth, crack free ceiling you really need to remove those tiles and sheetrock. Priming with an oil based primer then top coating with the paint of your choice can help limit the expansion and contraction that causes the cracking but since the top of the tiles are not sealed it only works so well.

 

You know as an experiment think about this. Get a roll of FibaFuse. it is a matt, not woven and comes in a roll either a yard wide or one meter wide, not sure. Spread on a coat of mud and embed this. Then give it another coat of mud, get it good enough to sand then sand and prime and paint.

That sure sounds like a lot of work for something that might not work. But I like to see other people experiment and learn from what they learn.

If this is glued on there must be a ceiling above. Plaster? Drywall? But why did they put this in a wash room? how big is the room?

 

It sounds like more work than just taking them down in the first place but I would definitely be taping the seams if I took on this project.