Paintable caulk for Goodhome Tough and durable matt white

[tireetim]

I've got some cracking between a ceiling and coving which have recently been painted in GoodHome tough and durable matt white. Can anybody recommend the best way to fix it? I have done a test on a piece of wood with both No nosense and Soudal decorators caulk but the paint cracks when I paint over both. Is there another product that this paint will go over? Otherwise, I have read on here somewhere that an oil based primer over the caulk might work - any particular one that you can recommend?
Thanks.

 

[foxhole]

Maybe spray with stain block .

 

[opps]

I am a decorator.

My go to caulk is Everbuild 125. When working with Dulux Trade emulsion, the paint seldom cracks. With other paints it may happen though. If it does, I apply a coat of shellac based paint, eg Zinnser BIN. As per @foxhole 's post. It is often used as a stain blocker.

Oil based undercoat will work but the curing time is much longer than shellac paints. During the summer, I can hit the caulk with the shellac and emulsion within 30 minutes. Using either, a downside is that emulsion will take longer to dry and you will probably need more than one coat of emulsion (because it is no longer soaking into the previous coat of emulsion.

Some caulk/paint combos are a mare. As I said, Everbuild 125 is my go to, I will not use their, everbuild's, "decorators'" caulk, ,it is rubbish (IMO). My fallback is the Geocell (Dow Corning) Painter's Mate. Almost double the price, but well behaved.

 

[tireetim]

Thanks Opps, I have just ordered some Zinnser BIN so will give that a go. Will see if I can get some Everbuild 125 at the same time. Thank for your help.