Emulsion Paint on top of Bitumen Damp Proof Paint

Discussion in 'Painters' Talk' started by Laura powell, Jan 8, 2019.

  1. Laura powell

    Laura powell New Member


    Thanks in advance if you can help. I have painted a few internal walls with black bitumen damp proof paint thinking it was as simple as doing a coat of that and then painting on top with emulsion. I know... how wrong I was. All the walls now look like a dried riverbed and have all cracked.

    I have been thinking about what to do because the reason I did this was to stop a previous damp problem that’s been fixed now since it kept coming through the new paint and plaster. To save having to skim again I was thinking how best to approach this now, can I simple just sand down the paint and do a mist coat and carry on as normal, do I need to do a layer of undercoat first? Do I need to get some pva glue? Do I really need to skim?

    Please help if you can!! Many thanks all!
  2. Isitreally

    Isitreally Super Member

  3. Laura powell

    Laura powell New Member

    Thanks although, only issue that this is really for outdoor use, this is for internal walls and I want to use normal emulsion :(
  4. Astramax

    Astramax Super Member

    Oh dear, you have now a huge problem................. damp is best treated at source, there is a way around this, can you post any photos as that would provide a far better idea of how to deal with the task ahead.:)
    Laura powell likes this.
  5. Laura powell

    Laura powell New Member

    Thank you for your help. It won’t let me post pictures- apparently too large for the server to process.

    The source of the damp has been treated however it left the walls in a horrendous state hence the paint.

    The stage where I am at now the walls look like this - but in white and I’m not really liking the texture - https://goo.gl/images/4qdCZ3
  6. Laura powell

    Laura powell New Member

    Also quite similar to this https://goo.gl/images/SeFw4f
  7. Astramax

    Astramax Super Member

    Messy and time consuming job but I am wondering if a wallpaper steam stripper might fetch the white paint and the bitumen off right back to the plaster, a hot air gun also may be worth a try.

    A product called Three in One Foil is a very good covering for damp walls, it has to be stuck to the wall like wallpaper with a special adhesive that sticks to damp. Once it has dried the foil is then cross lined with lining paper horizontally and once more vertically then decorated to you're chosen finish......long winded I know but it does the job!
    WillyEckerslike and Laura powell like this.
  8. Laura powell

    Laura powell New Member

    Thank you, so definitely no undercoat or plastering over what a mess!
  9. Astramax

    Astramax Super Member

    My view would be to remove the mistake as simply and best as possible, others on here may be able to offer other options.

    KIAB is the chap on here to advise you on how to load on pictures so he may be around soon to help.
    Laura powell likes this.
  10. Laura powell

    Laura powell New Member

    Thank you, I’ll hold on in hope of a hopefully easier solution and if not yours might be it. You can’t actually see the cracks from a distance just when up close but it’s not the best texture for a house. In the mean time ive uploaded a picture on twitter... here you go https://twitter.com/thejosephdixon/status/1082768608873324544?s=21
  11. KIAB

    KIAB Super Member

    Try 'Tiny Pic' http://tinypic.com/

    Bitumen damp proof paint on internal walls.:eek:

    No chance in hell painting them with emulsion, best option is off with the lot & replaster, or overboard wall(s) with plasterboard & skim.

    Here we go.:)

    Last edited: Jan 8, 2019
    Laura powell likes this.
  12. Laura powell

    Laura powell New Member

    Damn! The truth hurts o_O thank you if that’s the only option :(
  13. KIAB

    KIAB Super Member

    The bitumen will continue to bleed through, regardless how coats of paint you slap on it.
  14. Laura powell

    Laura powell New Member

    When you say sleeping through do you mean cracking again? And how long?

    A decorator has given me a quote to fix by using two thinned undercoat layers and then back to emulsion but I’ve read else where online it might not work.
    Astramax likes this.
  15. KIAB

    KIAB Super Member

    No, the oil/tar in the bitumen will leach out,as to how long, I don't know.

    Can't see two thinned undercoat layers and then back to emulsion working.
  16. DIYDave.

    DIYDave. Screwfix Select

    Even if that would work (which it won’t), hows that gonna solve the cracking issue ?

    What was the actual ‘thinned undercoat’ to be used I wonder ?

    Thinned out emuslion perhaps ?

    You sure this geezer is a decorator and what kind of assurance has he given you that his idea will work

    Even if it did work (which it won’t), likely to be temporary until the bitumen bleeds through the water based undercoat / emuslion in time

    Nightmare situation

    I’m wondering if a Zinnser primer (not sure which one) maybe 2 coats then papering with Wallrock Fibre Liner would work -

    Your thoughts please Astra :)
  17. goldenboy

    goldenboy Super Member

    Don't you put a wet coat of bitumen paint on, then blind it with silver sand and then plaster over?

    That would be easier than trying to strip the bitumen off.
    KIAB likes this.
  18. goldenboy

    goldenboy Super Member

    Could there be any possibility of using a heavy lining paper over the crazed surface?
  19. KIAB

    KIAB Super Member

    Use to many moons ago,I haven't don't that in years.:D
    And use sharp sand to blind & then render in old days.
    goldenboy likes this.
  20. goldenboy

    goldenboy Super Member

    Whatever the solution its definitely not going to be an easy one!
    Laura powell likes this.

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