Old paint coming away with new

Discussion in 'Painters' Talk' started by Jigarai, May 8, 2020.

  1. Jigarai

    Jigarai New Member

    Hello folks,

    I’ve just painted a room. In places the paint has come away with the old paint and it would seem the last person to decorate, didn’t mist coat on the then new plaster.

    I’ve started scraping it back. <sigh>

    Any tips to minimise the pain of stripping it all back and putting it right will be appreciated.

    Obvs I know to mist coat once I’ve got it stripped but any help on getting to that stage would be amazing.

    Also is there any way of knowing if this is a potential problem in other rooms before I start putting paint on the walls?

  2. Jigarai

    Jigarai New Member

  3. Astramax

    Astramax Super Member

    A strong adhesive tape like Duct Tape could be used to pull it off if it is very poorly adhered along with a flexible thin flat broad bladed scraper. I think this room may be a strong clue as the the other rooms but that may not be the situation.:)
    Last edited: May 8, 2020
    Jigarai likes this.
  4. Jigarai

    Jigarai New Member

    Thanks Astramax. It’s mostly coming off with a scraper with a bit of patience. In places I am coming to a stable edge where it’s not coming off with the scraper. I’ll try the duct tape tip on those bits, but if it’s well enough adhered to withstand the pull of duct tape, is it okay then to sand back and just repaint the exposed area up to that point?
  5. Astramax

    Astramax Super Member

    Yes, sand back the stubborn area's to the plaster and mist coat the whole area then you know it's 'job done' correctly.......................I feel your pain! :(
  6. Jigarai

    Jigarai New Member

    Tape test confirms it’s all got to come off. as you say Astramax, sort it properly then forget about it.

    Attached Files:

  7. Astramax

    Astramax Super Member

  8. DIYDave.

    DIYDave. Screwfix Select

    Can also try wetting the paint/wall/ is if your soaking wallpaper and then scrape to remove

    After all, it’s the water in the new coat of emulsion that is causing the paint to come away from the wall

    As wall not mist coated, there’s no adhesion between paint and wall, it’s just sitting on the surface of the plaster

    Give it a good soaking, the paint may start to bubble and ripple and then will make scraping a whole lot easier

    Indeed, it’s a pain in the arris :(

    Weird thing is though, the paint looks fine until you try and repaint some years later and then you find out that the wall hasn’t been properly prepped :mad:
    Jigarai likes this.
  9. Jigarai

    Jigarai New Member

    Thanks Dave! That’s useful- I’ll get my spray mister out and see how I go.
  10. DIYer2345

    DIYer2345 New Member

    Oh man you have my sympathy. I have no idea what the builder used on the ceilings in our road. 2 year old houses and several of the neighbours are having issues with paint peeling and bubbling when applying a fresh coat to the ceilings. Some have even applied 7 and 8 coats to the ceilings before they got a covering they were happy with. No way was i going to apply 7 coats so I stripped it back to bare plaster and started from the basics with a mist coat of diluted Wickes contract white and then it covered perfectly with two coats of Dulux supermatt.

    To strip the emulsion to bare plaster I used wallpaper paste (no nasty chemicals to burn or inhale) to soften the paint, covering 2sqm at at time and leaving it soak for 3 or 4 minutes (don't let it go dry) the old paint then peeled off with a 3 inch scraper in nice strips (in most places) some need two attempts. Washed the ceiling down with a damp sponge, gentle rub over with a sanding pad, repaired an small marks and then covered with a diluted mist coat using Wickes contract white and then it covered perfectly with two coats of Dulux supermatt.

    Make sure you cover everything and don't wear your Sunday best because it's a messy job.
    fff likes this.
  11. Astramax

    Astramax Super Member

    Sounds like you stripped off a contract matt (non vinyl) emulsion.
  12. DIYer2345

    DIYer2345 New Member

    Possible, it is a newish house, 2 years old. If anyone has any idea why the emulsion paint is peeling myself and 3 neighbours would love to know. It's only peeling in small patches and not all over. We have also had the small patches peel on the walls when painting and sounding down to plaster then applying new mist coat solves the problems.
  13. Astramax

    Astramax Super Member

    Comes down to the mist coat or lack of it.
  14. Jigarai

    Jigarai New Member

    Update- have just finished mist coating after stripping/sanding all of the paint off.

    Patience and perseverance were needed. About 80% came off with a scraper in great satisfying strips. The rest where the paint was better (but not properly) adhered took the time but wanted the result to be even. Jury rigging the dyson (gaffer tape obvs!!) to my sander to control the dust was a game changer!! Filler and decorstor’s caulk and more sanding to deal with any scarring. Zinser seal on the edges.

    I’m glad I persevered and got to this stage. Thanks for all the comments above. They’ve all be appreciated. I’ll post a pic of the finished product in a few days. :)
  15. DIYDave.

    DIYDave. Screwfix Select

    Thanks for the update - sounds like you’ve made good progress and patience is needed indeed - along with good loud music and liquid refreshment - works for me anyway :)

    Just make sure that all filler patches are feathered into surrounding wall level and no noticeable raised edges where filler stops/starts

    I like to run my fingers over the wall without looking and you shouldn’t be able to feel any difference where you’ve filled to original plaster

    The test though is once the mist coat has dried. Although it’s primary task is to seal the thirsty plaster, it does a great trick at highlighting any imperfections you may have missed during filling and sanding

    Although this may be annoying as you think you’ve finished all the prep and now you’ve started to paint - it’s better to correct these areas now, before your finish coat goes on

    So.... let mist coat dry, it’s likely to look patchy and uneven, this sometimes surprises people as they’re expecting a solid white background from a single mist coat - it ain’t gonna happen and it’s to be expected and all perfectly fine - again, it’s job it to seal the plaster and even out porosity

    Check the walls in good light for any areas you wish to give a bit more attention to / fill, sand as required / spot mist coat any new filler

    Some people give 2 mist coats

    If you end up with several patches of new filler across the walls - easier to give the whole lot a 2nd mist coat for sure

    Light rub down with P180 before finish coat goes on and a good dust down

    Hope all goes well and enjoy :)

    All that effort will be worth it finally !

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