Paint peeling from filled areas
 

Hi

I recently repainted the walls of my living room but I'm having trouble
with the new paint coming off in areas where there used to be a freeze.

Before repainting I removed the freeze and in places some of the paint
below came with it, exposing bare plasterboard below. I assume the
wallpaper paste used to fix the freeze loosened the paint, leading to it
coming off when I removed the freeze.

In the areas where the paint had come away, I knocked off any
surrounding loose paint, filled the area with polyfilla, sanded it
smooth and then painted. It's these areas that I am now losing the new
paint; it cracks and just peels off the wall. The polyfilla stays on the
wall. The areas were fully dry before painting.

What can I do to remedy this? I've read about sealing plasterboard with
a watered-down PVA mix; is that appropriate? Alternatively, are there
any fillers designed to be directly applied to plasterboard? The
affected areas are quite small, no more than a square foot or two in
total.

Thanks for any help.

Cheers,

Mark