UKC

Decorating my daughter's bedroom and having an issue with the paint on the walls and ceiling.

It's a new-build house (about 5 years old), and this is the first time it's been painted since the builders went round with trade matt white paint.

Did the prep work - couple of nicks in the wall filled and all of it washed down with sugar soap, rinsed and left to dry.

No problems doing the edges with a paintbrush.

Started rollering this morning and, in a few places, the existing paintwork has stuck to the roller and just peeled straight off right back to the plasterboard in a 1-2" strip.

Doesn't seem to coincide with the pasterboard joins.

So far, I've done the ceiling and 1 wall - Dulux silk emulsion, thinned a bit with water for the first coat.

Can anyone explain what the issue is - have I missed a step in the prep, or were the builders just slapping it on and hoping for the best? There's one place where it looks like it might have already been starting to peel anyway.

This wall won't be such an issue, as it's going to be wallpapered, but I'm dreading the same happening on the other walls, which won't. Any suggestions for preventing it?

Also, what's the best way of sorting it out? I've got some plaster sealer, which I was going to use before filling with fine surface filler and then re-painting.

Didn't have this issue when painted the other bedroom last year.

Thanks in advance.

Hacked-off LBS - was hoping to get all the painting done this weekend

Damp wall either when the original paint was applied or damp now. 

Maybe first coat wasn't a mist coat? First coat onto fresh plaster should be diluted down so it soaks in

Maybe first coat wasn't a mist coat? First coat onto fresh plaster should be diluted down so it soaks in. 

In terms of fixing it, sadly it's probably a case of get rid of as much as possible and start from scratch with mist coat

The issue is that it's a new build. Built to a budget, thrown together by builders that are barely competent in the shortest possible time, no care or attention to detail. If this is the worst thing that you find with the house then you're very lucky!

Not damp now - it's an outside wall, but would have seen signs of mould by now if that was an issue. Do remember one of the guys when we moved in saying that new builds need a long time to dry out.

Thought trade matt was specifically designed for new plaster, though? One of the guys that came to sort a couple of snag list items left me the end of a tin of Dulex Trade Fast Matt, which is pretty watery.

When you say get rid of as much as possible, it looks like that will go back to the plasterboard. Do I need to get it re-skimmed?

Weird that it's only coming off in a few specific strips.

Indeed. Didn't have this issue in the last house, which was also a new build - probably a better builder, though.

Have had a couple of issues with water leaks.

Either the no mist coat mention above -  or the fresh plaster was sized with very watered down plasters' pva. I did that once taking advice of a plasterer and it resulted in paint peel later. Never ever again! (And that's most expensive approach too!)

Cheapest white emulsion (or whatever you have very light coloured leftovers) hugely watered down to appearance/consistency of milk, like 60 or 70% water (i.e. 30 or 40% paint).

Paint this "milk" onto any bare plaster you have. It will be messy! It splatters! It trickles down your hand/arm! (you were warned). It should soak into the plaster like water.

Let it dry completely, then give it a second coat of the cheapest white emulsion you have watered down by 30% water (i.e. 70% paint). It is also horribly messy!

When that's fully dry you can paint as normal.

It does sound like a failure to prep or paint properly, and the proper solution is to remove it and start again. If you want to try and bodge it, and I have to say I would, then try sealing it with PVA. Dilute 1 part PVA to 5 or 6 parts water and paint it on. Be warned, it's like water so splashes everywhere. Follow with a coat of 1 part PVA to 2 or 3 parts water. This solution has worked on some pretty crappy substrates for me.

If you don’t fancy getting back to the plaster then Zinsser Peel Stop might be worth a try?

I have:

• plaster sealer
• matt while emulsion
• PVA

Would prefer to use up the plaster sealer first, if that's appropriate?

I don't know what plaster sealer is, I've never used it. The great thing about super-diluted PVA is that it soaks through stuff and stabilises underneath. I would say try this first, because it won't stop the later treatments working, but if you put a coat of sealer on first, you can't then go for the dilute PVA.

It's coming off paper, not plaster? Weird.

I painted my fresh plaster in chalky matte trade emulsion, thinned for the first coat. Colour over the top doesn't stick well, the white seems to act as a release layer. Masking tape pulls the colour off the white in sheets. Worse things happen at sea but it's still very annoying.

With your problem I'd scrape back to find solid adhesion then thin the paint edges with fine sanding. Go over the area a couple of extra coats to further soften the edges. I had to do this in my bathroom where my wife took it upon herself to paint fresh plaster with zero prep and a somewhat colourful approach to detail Not perfect but from a couple of feet away not eyecatching.

Jk

I would still dilute. I don't really trust that even the trade stuff will substitute the mist coat. I dilute the mist coat quite a lot. It's a pain to work with, really messy, but seems to work best.

So was there a skim on top of the plasterboard and that is also peeling off? I would get in with a scraper and flake off whatever you can. 

Yeah, I have had that in some rooms in our house which hadn't been decorated properly in the first place. It doesn't seem to come off uniformly, don't really know why. But it is really annoying!

Interesting that you and CantClimbTom seem complete opposites on diluted PVA - unless I'm missing something?

Problem is I've no idea how much what I've got left has already been diluted, if at all.

I'm guessing it was skimmed - I'd assume it would have needed to be to level it, or you'd have a ridge where the jointing tape is.

Ok, so I think I'll scrape off what I can from where it's already peeled, try the mist coat with the trade matt I've got (I'll water it down a bit more) and then fill with fine surface filler to level it. Will need to be careful not to damage the exposed plasterboard. Won't be too huge a problem, as that wall is going to be covered (ultimately) with highly patterned wallpaper - it's the rest of the walls I'm not worried about!

It sounds very much like the original  never dusted/brushed the plasterboard properly after it was sanded after taping and filling.  There’s no need to skim the walls if it’s done properly.   They also never put a sealing coat on first before painting.

its a total pain!  You really need to fill the areas where the original paint has stripped off so that they are flush with the surrounding areas otherwise it will show through whatever you do on top of it.

the bad news is there’s a high chance it will happen again as you work your way through the rest of the house in time to come.  Good luck with it.

If the house is only 5 years old, the wall lining will most likely have just been taped and filled. It's pretty rare to skim coat it too. The vertical joints are taper-edged, so when they are then taped, filled then sanded down, it's flush with the main plane of the adjacent boards and don't sit proud of them. 

Thanks - that looks exactly the situation, although don't think it's been sanded down "quite" flush to start with, but not far off. Removes my worry about having to get it re-skimmed, anyway.

After a bit of careful scraping, it seems that the paint has come off in 2 strips either side of the plasterboard joints - probably correlates with Nowler's point about not clearing the sanding dust properly. Outside those areas, it seems sound.

It does look that way. Although Tom's case was on new plaster, which I have never used PVA on. I've always just used a mist coat. My use for PVA is on old flaking, dusty or peeling surfaces, and it's been great. I've decorated over stuff that really should have been stripped back and skimmed over, and it still looks fine.

It's worth mentioning that the only difference between trade paint and DIY paint from the same brand is that the DIY paint is diluted a bit. Trade paint is thicker, which allows a decorator to thin it appropriately for the situation. DIY paint comes pre-thinned to work OK out of the tin in most circumstances.

So don't ever use trade paint neat on new plaster! That's asking for it to dry in ridges and fall off.

So, can we assume the flaked paint has taken the dust off now, or do I need to do any more prep before applying a mist coat?

Yeah. I'm guessing that should be done "after" the mist coat?

Didn't have that problem in the other bedroom I've painted, or the bit inside the wardrobe of another bedroom, so hoping that I was just unlucky with that room - but now prepared in case I get it elsewhere.

I'd light sand (320G) the whole area - sorry!

If the sanding lifts the existing paint then you have to keep going until you hot solidly anchored paint.

Then paint over normally.

Do NOT reskim onto the unreliable surface!

Bit late to this and it sounds like you're on your way to a solution, but I'd suggest doing a test patch with whatever method you've chosen.  Dry it for a day and see if it scrapes off with your fingernail.

I'd suggest that if the unsound paint is uniform around the tape joints, they didn't allow the plaster to dry enough before painting, so that paint never properly bonded to the plaster.  

I'm a house painter and I personally use a primer on plaster, as opposed to a mist coat.  Primer is cheaper, seals porous surfaces, and creates a good bonding layer, but I'm sure a mist coat will do the trick as well.  Most primers and pvas are ready to top coat in 30 mins.  If you go for a mist coat, keep in mind that bare plaster will absorb all that moisture from the excessive diluting so make sure it dries out before going for the top coat.

Thanks,

I've rubbed down the edges and no more paint flaking off. Wiped over with a damp cloth to remove the dust and left to dry overnight.

Torn between a mist coat (using some white emulsion I already have, so essentially free) and buying some primer (and if so, what). The exposed bit is the paper cover of the plasterboard, rather than plaster itself.

If there's no exposed plaster, just the board, then probably a mist coat will do you fine.  Honestly no need to thin it down that much to where it's spraying and dripping all over the place.

I work in the States so not experienced with all the UK products, but I see they carry Zinsser primers at BnQ, and they work great, for future reference.

Good luck, hope it comes out well

Thanks.

I think my quandary is whether to use a mist coat or actual primer, given that I'm going to have to fill with fine surface filler afterwards to bring up to the level of the un-peeled paint.

Head says primer would be better adhesion, but trying to avoid another trip to B&Q...

Somebody mentioned it previously but I'd zinsser peel stop any exposed edges if it's not coming off in sheets. Fill sand any areas that have peeled and then decorate 

Do not put PVA anywhere near a surface you later want to paint.

Zinsser bullseye if you want to go to town with a primer. 

Thanks all for the thoughts.

After considering options and rejecting any thoughts of PVA, I decided to try the easy option and thinned down a bit of the trade matt I've got 50% with water and painted that on. Seems to have soaked in ok and dried such that it isn't scraping off with a fingernail.

Going to give it another coat and see what that looks like.

I've also been separately recommended Polycell SmoothOver as an alternative to filler - looks like a good (but not cheap!) option. Anyone used that before?

I’ve always found taping and filling compound by far the easiest to use and sand.  Unfortunately, it’s only sold on large tubs 😢