Filler showing through emulsion a year later

[Dingdong99]

We had most of our house painted a year ago, and just in the living room, these patches have appeared a few weeks ago

It looks like the filler is showing through

There's no damp in there, so I don't think it's to do with that

I've checked with the decorator and he's scratching his head

Does anyone know why this might be? Seems odd that it's only happened in one room

Sorry no help but marking as we have this too. It’s on a chimney breast of a place we have just purchased. Previous owners said it’s where they painted over a cement repair before it dried out properly but I’m not convinced it’s not damp even though the survey didn’t spot it.

I'd try repainting that wall.

Looks like filler is grinning through the top coat.

Google it..it happens..

Lightly rub back then seal filler with coat of Zinnsner BIn.. leave to dry then recoat..
may have to repaint whole wall to blend in..

..if it was painted a year ago and wasn't sealed initially, then the filler can absorb and hold moisture from the air at different rates, hence different colour shades..
.. anything in that room producing more moisture, damp air recently ?..

Thanks all

Yes Zinser that I agree. Light sand then 2 coats ideally, second with a roller if you can be bothered.

@Lonelycrab which Zinsser do you recommend? I’ve had a look online and can’t decide if it’s Bin or 123 that’s the best for internal plaster patches …..

Have only ever used bin, but that’s on all sorts of things with staining etc. always been good for me. But it is quite milky, more so than normal paint so sometimes a few coats is good.

Thanks - I’ll give it a go with bin and 🤞no more stain!

@Karmatime just re read your post, one thing to say as I had a chimney breast with problems too, it was caused by hygroscopic damp (google it). This maybe beyond just what you can cover up with ZB as it’s an ongoing damp issue. It might be ok just sealing, but in our case the solution was to strip all the plaster off around the chimney breast and re plaster, I think our builder used a layer of tanking (not sure) and then plaster on top. Good luck.

Thanks @Lonelycrab - I’m hoping it isn’t the salts. It’s just a patch but there is some bubbling of paint coming. I’m going to try sanding, priming and repainting to start with. It’s a working fireplace with a fairly new wood burner and it and the flue are under guarantee. I’ve also invested in a dehumidifier, not specifically for that issue, but hope that might help if the issue was caused by condensation in the first place?

@Karmatime Yes dehumidifier is exactly what we did, seemed to keep it in check a bit before we had it redone.
It might not be as bad as I said, so do what you’re doing and see what happens.
I don’t think it’ll be anything to do with your new burner, as far as I understand it, it’s when the brick absorb the salts over long periods of time ie decades and it turns them kinda sponge like, they then start absorbing any moisture. If it’s not too big you’ll probably be fine. At the end of the day it’s just a small cosmetic problem, not a major issue. So see how you go.