What's causing this? Distemper?

[fernicarry]

Undercoating the ceiling and this is happening in a few areas. Not the whole ceiling, but in quite a few spots. Could it be a reaction to distemper?

If I scrape it when its wet then large areas unravel but if I leave it to dry out it mostly calms down again. After a rub down with sand paper and a skim of filler it will usually take the undercoat second time around, or third, or fourth.

Once its all covered with undercoat will it stay sealed so I can safely move on to the top coat?

 

[a twig]

Could be lots of things - assuming it is plasterboard - in a similar situation I just slapped a load of this stuff on my ceiling and the problem went away. Apply generously with a brush, when I rollered it on it wasn’t as effective.

Zinsser Peel Stop Primer Paint

Is peeling, flaking, dusting or chalking a problem? Use this Zinsser Peel Stop clear binding primer to deal with problem surfaces – it forms a tough acrylic film that stays flexible and helps prevent peeling by letting moisture escape.Suitable for use surfaces indoors and outdoors, Zinsser Peel...

www.toolstation.com

 

[fernicarry]

Pretty sure its not plasterboard. I tried Sika Bond yesterday because I had a jug of it in the garage. It seemed to help somewhat.

When I went back to the areas that blistered today to make good, I was hard pressed to find them. Not nearly as prominent as earlier on. I'll see if it takes another coat of undercoat tomorrow.

 

[Stevers]

We have a selection of ceilings from 1879 which have layers of coatings that adhere poorly leading to large flakes detaching. I had blamed something that I thought was 'Ceilingite', but that turns out to be a distemper so probably not the culprit. Wikipedia, in as far as it is to be trusted, states that whitewash/limewash is prone to blistering when overpainted with latex paints, so I suspect our difficulties with old house ceilings are more likely to be related to a layer or layers of limewash.

 

[mardinor]

In future, I'd sand first then apply a white adhesion primer as the 'undercoat' eg Blackfriars problem solving primer or Benjamin Moore Stix. Did the trick for us in same situation. We found rolling impossible but brush painting OK.

 

[a twig]

I liked the Zinsser one as you can paint it over the existing peeling paint and it sticks it back down.

 

[fernicarry]

I'm slowly beating this into submission mainly by sanding and skimming the affected areas. I'm thinking perhaps its a very old lining paper because I can now see straight lines emerging. If it is paper then its incredibly thin or maybe its delaminated and a layer is peeling off.

First time I've done any decorating in this house. As always it has a surprise in store... In future I may just assume the worst and go straight in with Zinsser or similar.