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Paint cracking over caulk and Zinsser

Hi, I have just had my hallway and landing walls plastered about two months ago. Between the ceiling and wall the finish was shabby, so I ran a thin bead of caulk along it. I painted over this with Zinsser bin and then applied two coats of Leyland hardwearing white matt emulsion. When dried there were cracks everywhere. I then bought some Zinsser peel stop and went over it with that, but again after painting the emulsion, the cracks were back. I then caulked again with a different brand of caulk, painted with Zinsser peel stop and then with Zinsser bin, but again after the emulsion is painted on, the cracks reappear. The Leyland emulsion paint was not cheap at £27 for 5L and I am going mad at what to try next. Any help would be most appreciated.
Kind regards, Kev.

Hi sorry to see your having theses problems, I had the same, must of been a good few years ago, a job i painted, I came back the next morning, the customer pointed out crazing, from that day i changed from a cheap caulk to good quality caulk,Den braven you can buy from decorating direct, never had a problem after that.I would prime with a oil based undercoat. One other tip i will give you,i will try and find a picture, because of movement on stairs i used toupret elafib,in tube never failed. Cheers

Excellent! Thank you for your reply darlic. I will buy some and try it. It’s been driving me mad. Thank you for your answer, it is much appreciated.

Kind regards, Kev.

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Caulking direct onto new plaster wouldn’t be the best move, as the plaster would suck the life out the caulk.

You are “in deep” with all the product combinations. I’d try rake out your first bead, put a thin coat of emulsion on any bare plaster, and as Jason says, use a decent caulk let it dry for a day or two and bring out the old fashioned oil undercoat and emulsion paint over that when dry.

This article goes into the detail of why emulsion cracks over caulk.

Cheers Andy. I did mist coat the plaster, so the caulk was not going on to bare plaster. A friend suggested using external frame sealant instead of caulk, as it seems like it is the emulsion cracking and not the caulk, as the caulk has been painted over twice with zinsser bin and twice with zinsser peel stop and the emulsion is still cracking.
Kind regards, Kev.

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To be honest if you come across the situation next time, just clean area spray water into the cracks and fill with Toupret tx110.

I actually have some of that filler in my garage that i bought from Toolstation. I will try that first. Cheers darlic.

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I stand corrected on how you prepared before caulking. :+1: Yes, it seems emulsion paint cracks in this situation because of surface tension issues between the emulsion and what it is going over.

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