Priming Old Plaster (poor paint adhesion)

[SK54]

Hello,
Looking for some advice about primer.

We have stripped the walls in our 1930s house. The walls are in quite good condition, nice and flat.

In one room, we have sanded down, filled any minor dents, painted one coat of basic white emulsion, then our colours on top.
The problem is, the colour does not seem to be sticking very well and comes off with the slightest brush (the white stays on).

I am assuming we should have used a primer?
Whats the best way to go about this, primer + white + colour, or, primer + colour?

Want to get it right going forwards.

We are only the 3rd owners, the walls were all covered in wallpaper and im not quite sure of the type of plaster used - it is kind of a grey colour - photo attached

 

[JohnD]

Did you wash off the old wallpaper paste?

Is the difficult room the bathroom or kitchen?

Have the walls been previously painted? Distemper will scrub off with hot water but not with cold, and has a distinctive unpleasant smell during the scrubbing. It is usually in pastel colours.

Creamy coloured plaster is probably lime.

The first coat on bare plaster should be thinned with water to soak in, and should be Matt, not silk.

 

[SK54]

Did you wash off the old wallpaper paste?

Is the difficult room the bathroom or kitchen?

Have the walls been previously painted? Distemper will scrub off with hot water but not with cold, and has a distinctive unpleasant smell during the scrubbing. It is usually in pastel colours.

Creamy coloured plaster is probably lime.

The first coat on bare plaster should be thinned with water to soak in, and should be Matt, not silk.

Thanks John, yes walls were clear of paste, and not previously painted. Room is a living room, no damp issues.
Lime is what I was thinking too.

I am wondering if it is an issue with the coloured paint sticking to the white?
As the white paint seems to be sticking fine - it is only the colour that is coming off.

We used crown trade matt white, and leyland trade matt for the colour.

 

[JohnD]

I can't think what the trouble is, then.

You could, experimentally, try lightly wiping the walls with a very fine abrasive paper, say 600 grade, to dull the surface.

The only primer you should need on clean, bare plaster is mist coats of Matt emulsion thinned with water.

 

[SK54]

Hmm, okay.
I'm wondering if the issue is the emulsion? I'm now reading that if it is lime, better to use breathable paint such as clay paints.

 

[JohnD]

Don't know. I have had a house with lime plaster, but now I think of it, any painted walls had lining paper on them (some were distempered).