Why does ceiling paint curl and flake (and how to I stop it)?

[Ed Sirett]

I painted a concrete/plaster ceiling last year with do coats of white matt emulsion. This year it has curled up and flaked off.

What did I do wrong? The location is a bathroom with a shower?

[Pete C]

Was the concrete/plaster new? If so it's alkalinity could have caused the peeling. Also caustic strippers would have the same effect.

Maybe worth trying an alkali resistant paint/primer/sealer. Eg:

Or could the ceiling be painted with distemper? This is too powdery to paint over and needs sealing with PVA or stablilising solution.

cheers, Pete.

[meow2222]

Tha cause is lack of sufficient adhesion, but that has more than one possible cause. Eg dirt or grease on the ceiling, or a glossy oil painted surface. Also emulsion will come off under the influence of some detergent type things, especially ecover. I'd try a thorough surface wash, and maybe a very quick run over with a fine sander to ensure a good key. If all else fails there are problem primers, but I prefer to avoid them as theyre bulky, and usually unnecessary time and expense.

NT

[Stuart Noble]

Dulux often does this IME.

[Bob Eager]

Classic reason is that it's been distempered. I speak from bitter experience...

[Ed Sirett]

Thanks for the help guys. The ceiling was old and covered with black mould. So I scrubbed it with an anti-fungal wash. Then I painted it with two coats of matt vinyl emulsion (which was a specialist antifungal paint - McPhersons IIRC).

Reading your posts it looks like I might have left alkaline deposits (cleaning materials) on the surface.

Anyway to cure (when the time comes - the tenant is OK about it ATM) looks like:

1) Scrape all loose and flaking off. 2) Scrub with plain water. 3) Lightly sand. 4) Rinse down with water again. 5) Oil based Alkali resisting primer. 6) Two coats of bog standard vinyl matt emulsion.

[Stuart Noble]

What's a CORGI doing buggering about with all this? I thought you guys had more lucrative things to do :-)

[Pete C]

Maybe the paint wasn't suitable for high humidity areas, could be worth a quick call to them to check.

A friends bathroom ceiling has been like this for some years... it's a flat in a fairly old block again with concrete/plaster ceiling.

I'd tend to agree, if the old paint continues to peel, it's not worth overcoating with something expensive.

Even so, a bathroom paint should be more resistant to humidity, you don't want the new paint to peel off the above.

Also check it's OK over oil based, might need keying with a paint prep pad.

Still, if mildew reoccurs, it might be worth using mildew resistant bathroom paint, eg:

I'm sure I've seen a Dulux version much cheaper tho.

cheers, Pete.

[Ed Sirett]

My core job is to run several flats both for myself and others. In fact the CORGI thing was more a matter of necessity (some years ago) when my erstwhile trusted gas fitter retired. I could not find anyone to do the job that wo0uld answer my calls. I guess, it's a pretty sound business policy that if you can't find someone to do something then you should start a business doing it for yourself and offering the service to others.

Indeed I could fill up all all day everyday for the rest of my (somewhat shortened) life doing gas and heating but that isn't the target.