New plasterboard coving cracks at edges when painted

[dmjones500]

Hi guys,

I fitted my first set of plasterboard coving recently. My corners weren't great, but I used additional coving adhesive to hide my novice handiwork.

I caulked the edges of the coving to fill any remaining gaps and started painting it (normal white emulsion). However, after the second coat I noticed some fine hairline cracks appearing at the join between the coving and the wall (and the ceiling), plus in the patched-up corners. Last night I tried a third coat and the same thing has happened when it dried.

Note: there are no cracks appearing along the main body of the coving. Just at the joins and the corners.

Does anyone have any idea what is causing these cracks? I've painted over caulk before and didn't have any problems as far as I can remember.

 

[sparkwright]

What adhesive did you use to fix the coving to the wall and ceiling?

 

[dmjones500]

What adhesive did you use to fix the coving to the wall and ceiling?

Just regular coving adhesive. I bought a 5kg bag of powder from Travis Perkin. I filled the cracks with decorators caulk.

Looking closer at the results of the third coat, it looks slightly better. I think I'll fill the cracks with fine surface pollyfilla and will try a fourth coat after.

Unless, of course, anyone has a better suggestion?

Thanks,

Duncan

 

[roughcaster]

What did you put the coving onto,, painted walls?? Did you provide a key/rough surface, along the wall/ceiling line, for the cove adhesive to grab onto??

 

[benno5]

its your emulsion cracking on the caulk mate run a thin coat of oil based undercoat over where youve caulked let it dry for 24hrs and give it another couple of thin coats of emulsion and it should be fine

 

[dmjones500]

its your emulsion cracking on the caulk mate run a thin coat of oil based undercoat over where youve caulked let it dry for 24hrs and give it another couple of thin coats of emulsion and it should be fine

Sounds like the exact problem. Unfortunately, I rushed ahead and filled the teeny cracks with fine surface filler. Will that provide a sufficient barrier between the caulk and paint, or should I still do an oil based undercoat?

Thanks.

 

[benno5]

it may well be ok ,i'd do a test area to find out ,and if it's still happening go down the undercoat route

 

[dmjones500]

Ok, the filler seemed to be sufficient. Thanks for your help, will bear in mind in future.

I guess I normally gloss over caulk (e.g. Skirting) so hadn't come across this before.