1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Chalking / Flaking paint

Discussion in 'Decorating and Painting' started by Craig24, 12 Jan 2021.

  1. Craig24

    Craig24

    Joined:
    16 Dec 2016
    Messages:
    44
    Thanks Received:
    0
    Country:
    United Kingdom
    Hi all,

    I've read a few similar threads to the problem I have but having tried other solutions I'm stuck.

    We have a 1 wall in a room that we painted when we moved into our house. All the paint went on OK and was fine for around a month, then 1 wall (the only external wall in that room) the paint started becoming chalky, if you brush it the paint comes off like dust.

    I scrapped all the paint off, painted it with Zinsser Peel Stop, then mist coated it with Leyland Trade Contract Mat, then painted with 2 normal coats of the same. It was fine again for around a month then started doing the same thing again.

    Any help much appreciated.
     
  2. Sponsored Links
  3. Bonni

    Bonni

    Joined:
    11 Jun 2018
    Messages:
    407
    Thanks Received:
    82
    Country:
    United Kingdom
    What about trying Zinsser Guardz.
     
  4. opps

    opps

    Joined:
    16 Jun 2006
    Messages:
    4,529
    Thanks Received:
    708
    Location:
    London
    Country:
    United Kingdom
    It may be the case that at some point the wall was damp. The damp can cause the salts in the plaster to rise to the surface (known as efflorescence). You can purchase neutralising agents

    https://www.dampness-info.co.uk/damp_shop.htm#Saltneutraliser

    You may need to sand the paint off though, the product description says it doesn't penetrate through paint.

    Is the problem local to a specific part of the wall? is it an external wall? Photos might help.

    Peelstop does come with a guarantee and it is supposed to work with chalky walls. It might be a good idea to contact them (IIRC currently via email only- covid). I suspect that they might conclude that there is on-going water ingress.

    https://www.zinsseruk.com/core/wp-content/uploads/2016/12/Peel-Stop2.pdf
     
  5. Craig24

    Craig24

    Joined:
    16 Dec 2016
    Messages:
    44
    Thanks Received:
    0
    Country:
    United Kingdom
    Thanks, it is specific to one wall and it is an external wall, either side of a window.

    I did put a small hole in the plaster back to brick to see how it looked, all the plaster looks dry and the wall isn't any colder than the others to touch.
     
  6. Craig24

    Craig24

    Joined:
    16 Dec 2016
    Messages:
    44
    Thanks Received:
    0
    Country:
    United Kingdom
    Some photos
     

    Attached Files:

  7. JohnD

    JohnD

    Joined:
    15 Nov 2005
    Messages:
    68,738
    Thanks Received:
    3,819
    Location:
    Crossgates
    Country:
    Cook Islands
    How old is the house?
     
  8. Sponsored Links
  9. Craig24

    Craig24

    Joined:
    16 Dec 2016
    Messages:
    44
    Thanks Received:
    0
    Country:
    United Kingdom
    1920's. It appears to be the only wall in the house I've found so far with this issue.
     
  10. JohnD

    JohnD

    Joined:
    15 Nov 2005
    Messages:
    68,738
    Thanks Received:
    3,819
    Location:
    Crossgates
    Country:
    Cook Islands
    It's old enough to have had distemper on the walls, though I can't see it.

    Other possibilities are wallpaper paste or PVA glue.

    All of these will come off if scrubbed with hot water and the residue scraped off.
     
  11. Craig24

    Craig24

    Joined:
    16 Dec 2016
    Messages:
    44
    Thanks Received:
    0
    Country:
    United Kingdom
    Thanks, last time I scraped it back to plaster and coated with peel stop. I didn't notice wall paper paste but I didn't scrub with hot water either.
     
  12. Craig24

    Craig24

    Joined:
    16 Dec 2016
    Messages:
    44
    Thanks Received:
    0
    Country:
    United Kingdom
    So scrape it all off, sand it, clean it with hot water. Then should I apply a neutralising agent first?
     
  13. Wayners

    Wayners

    Joined:
    24 Oct 2020
    Messages:
    240
    Thanks Received:
    66
    Country:
    United Kingdom
    Please don't buy contract paint unless you want surface to breath (peal stop will put a stop to that) it's not good as a primer and designed for new damp builds to dry out. Either follow your chosen paint data sheet for dilution to prime or use an acrylic primer. Some DIY paints can't be used to prime and it says so on can (who reads) and contract matts can need priming as some durables won't take to contract paint too well.

    Try Wallrock Thermal Liner to insulate applied with ready mixed paste over the wall and something better that contract paint over. With any luck that will lower the dew point by insulating the wall and the paint will be fine..

    You can buy damp meter cheap to check wall if needed but looks like condensation to me on that outside wall
     
  14. Craig24

    Craig24

    Joined:
    16 Dec 2016
    Messages:
    44
    Thanks Received:
    0
    Country:
    United Kingdom
    Thanks but I’d really like to not have to use lining paper.

    Last time I scraped off the paint and cleaned the walls before applying, I’m sure there was no wallpaper paste on the walls. I don’t get any condensation on the window at all either?
     
Loading...

Share This Page