Help - DIY novice - peeling paint

[FamilyOhNo]

Help and advice needed.

Painting hall walls white with valspar paint. Come down this morning to patches of peeling paint ....

Can anyone suggest what’s gone wrong please and how to rectify it ?

What was on the walls before you painted them?
I'm not an expert at all. Did you use an undercoat? Possible damp patch? Does it feel wet?

Doesn't look like it from the photos, but did you paint on to bare plastered walls?

Yes, how did you prep the walls and what were they like before?

I'd say its damp. My 150 year old cottage has patches like this. I primed my plastered walls first but still have patches on walls which are outside walls which are flaking just like yours. Regardless of the prep if the walls are not insulated or lined and just plastered brick/stonework then the damp will always find its way back through gaps in the outdoor pointing or maybe in your case the window sill.

Walls were rubbed down and filled. It’s all over though ... upstairs downstairs different wallls, some interior some exterior.

Paint on previously was dulux timeless.

No idea why. But doubt it’s damp.

Did you wash the walls down with anything

I'd try sanding back the patches gently and repaint. Just do a small area first. If that doesn't work undercoat it and repaint again, do a patch first.

Valspar have a customer services line who might help. How many coats did you put on.

What type of paint was on the wall previously? This sort of thing can happen if you paint Matt over Silk without using a primer.