[Neilp85]

A couple of years ago I painted feature wall blue with oil based paint. I'm now repainting it white with emulsion but it keeps flaking where I cut in. Initially I sanded, washed, undercoat and then painted it.

I've thoroughly re-sanded those flaking areas and spread the paint more thinly twice over, but to my dismay its still flaking in the same places.

Any help/advice would be appreciated!!

 

[mark sr]

Assuming it was an oil base enamel and not a flat oil you can't successfully apply latex paint over it without using a solvent based primer first.

 

[Gymschu]

+1 on what @mark sr said. The old oil-based is likely hard and glossy. Latex has a difficult time sticking to that type of surface. Use some Zinsser Cover Stain or some Zinsser BIN shellac. At the very least, use a latex BONDING primer like Zinsser's 123. If you just used a regular latex primer, and it didn't have bonding properties that's where your problem lies.