Paint keeps powdering

[perrymeister]

I have a recurring problem on a small patch of internal wall near my kitchen window.
I noticed that the paint had powdered and stripped it back and repainted it. Within a short time it had powdered again. I stripped it back and put down an undercoat this time but again it has powdered. What can I do. Is there a solution I should put on it?

 

[mattysupra]

sounds like damp. Check there is no water getting in through window frame. Re seal.