Slump and cracks in filler visible after mist coat

[JamieB3009]

Hello,

I have recently had my kitchen freshly plastered. I left the plaster 8 weeks to dry and then went round filling and flattening any cracks and defects before mist coating. For the cracks i raked them out to a 'V' shape with a stanley knife and then filled with easi fill and filled again until they were full. I then sanded them down and checked for flatness with my hand. They appeared flawless, however, after mist coating i noticed they appear slightly lower now (see first photo). Almost like they have slumped. Also some of the cracks have reappeared. What would be the best way to sort these? I dont want to have to go into major surgery if i can help it. Would a flexible filler such as toupret fill flex be best. As these have only had a single watered down mist coat, would further coats of full thickness paint hide them?

Thanks..

 

[Wayners]

Cracks need to be dealt with before plastering or they come back very soon after skimming.
There are no shortcuts to fixing.
Bungalow or house?

 

[88v8]

That second one looks like a plasterboard join that should have been scrimmed, or perhaps over a stud.

In a corner or against wood for instance, I use decorator's caulk, in a tube, flexible and seems to last well.

In plaster, good old Polyfilla, the powder stuff, it goes off quickly, grips well, sands flat. Don't mix up too much at once, as I say, it goes off quickly. Wait until it goes white before sanding.

However, if these are cracks in the underlying brick/block, as Wayners said, they will just print through again. In that case, paper the wall, first with scrim paper and then a coat of ordinary paper, preferably vinyl to handle steamy conditions. Stagger the joins.