Paint crazing on Caulk

[Dan9899505]

Recently put up coving in room. I filled the gaps with decorating caulk. Two weeks later I painted it with Dulux Matt emulsion. However the paint crazed. I then thought I might need to prime it with PVA to stop this. However it has crazed again. I have contacted Zinzzer and Leyland about using their Primer, however they say now I have PVA'd it that it would be no good. I now know for future that these products would work but for now need to know what to do to solve my mess in this room?

thanks

Dan

 

[ironsidebod]

PVA and decorating do not mix. There is never a good reason to put PVA on anything you are going to paint, regardless of what many plasterers/professionals/bloke in the pub might say. It causes sooooo many problems.

Can you dig out the caulk, sand the coving edge and re-caulk? Possible to wash off the PVA and go again? If the paint cracks on good quality caulk then you can try painting with an oil based undercoat and go from there. In fact this might be your easiest option without messing with what's there already.

 

[chappers]

caulk can shrink and crack as it dries, particularly on dry surfaces such as new plaster, coving, coving adhesives etc.
Best practice is to get a coat or two of paint on first to reduce the suction from the substrate before caulking, then finish painting over the top.
I would give it another go with some decent caulk and then repaint

 

[amfisted]

Another shout for "dig out and start again".

I've been painting and decorating my own houses for years. During the course of those years I've occasionally used PVA to seal an elderly plaster wall in advance of painting with emulsion, and until recently I managed to get away with it.

However, it was a simply horrible experience with a newly plastered fireplace that finally persuaded me never to use PVA when preparing a wall for painting ever again.

After applying emulsion I had crazing, cracking, peeling and the whole gamut of spontaneous paint self-removal, and it wasn't till I stripped the wall back to the brick and DIY-plastered it again myself that the problem was solved.

Basically, if there's PVA in there somewhere you're going to continue to have problems.

 

[opps]

caulk can shrink and crack as it dries,

I get the impression that the paint has crazed rather than the caulk cracking.

It is very common.

I now use Everbuild 125 caulk which is OK with Dulux Trade emulsion but a couple of weeks ago, i had to use the 125 with Crown Trade and the paint crazed.

 

[opps]

I have contacted Zinzzer and Leyland about using their Primer, however they say now I have PVA'd it that it would be no good.

You can use Zinsser BIN over it.

I have used BIN over PVA loads of times. It is shellac based and thus doesn't reactive the PVA. You could even use oil based undercoat, it will be cheaper than the BIN but will take longer to dry.

 

[darkan9el]

I've found thinning the paint a bit normally works, dulux paints can be quite thick.