Hi there
Back in late January I had my house rewired. I was concerned that the chases weren't deep enough - in places there was only about 4 or 5 mm depth over the new wires for plaster. However, the plasterer I employed did a seemingly good job and managed to build up the plaster a bit either side of the chase with the worst examples.

Finally, after doing lots of work to my sitting room I am now decorating it. I was putting a watered down coat of emulsion over the patches of new plaster, when after a few minutes (joy of joys) a piece of plaster came off on my paint brush. So, I counted to 10 and got my scraper out. I scrapped the plaster away right up to the line of the chase. It was solid there. So now I have a vertical stepped line of about 5 mm running down from the ceiling to the socket. Great. I don't want to sand it (I'm trying to decorate). So have smoothed it out a bit down the length with polyfiller.

Should the plasterer have used PVA or something then? This plaster was not bonded to the painted wall at all, only in the chase!!

Would love to know whether that's what went wrong?!

Best wishes,

K

The plasterer should have put PVA in the chase, then undercoat plaster, before finishing using multifinish usually. I am assuming that the multifinish has failed where the chase meets the paintwork and that he has overlapped the plaster onto the existing paint.

Multifinish is not a strong material and does not bond well to paint. If it has failed where it overlapped, it is because it shouldn't be used that thin, especially on paintwork.

I usually pva, then fill the chase with bonding plaster and strike off with the trowel so that non of it is protruding. When it is dry, I then fill over the top of the chase with Easifill, sand and fill again. The easifill can be put on thin and doesn't need to be second coated and it will bond to the paintwork. It is easier to apply and can be sanded to a flawless finish.