Please help, how to waterproof a pebble dashing exterior wall?

Discussion in 'Painters' Talk' started by cl0391, Feb 24, 2015.

  1. cl0391

    cl0391 New Member

    Dear Professionals :)

    Well, I have this old flat with pebble dashing exterior wall. considering how old this flat is, i don't think the previous builder have ever applied any water proof product on the exterior before.
    so the question comes... don't laugh at me if it is too noob...
    What can i do to my exterior pebble dashing wall, to make it not so vulnerable to weather?
    paint? any products you pros recommend?

    any advice will be helpful.
     
  2. What makes you think your pebble dash is 'vulnerable'? Is it showing any signs of water penetration?

    Has it ever been painted or is it bare render?

    Usually paint is all that's required for protection - beware of using anything like Thomson's Waterproofer, etc without full advice.

    It might be ok to use, but make absolutely certain...
     
  3. cl0391

    cl0391 New Member

    hi, devil... lol come to help me on this topic again.
    well, the reason is, after I plastered interior side 2 weeks ago, it still appears wet marks on 80%+ area, the only reason i could think of is the water comes from exterior side, that continuously moisturize the interior side , stops it getting dry.

    i don't think the previous owners have ever painted it, i consider it as bare render.
    I went to screwfix today to get paint, but the staff told me that i should clean the exterior wall, make it dust free, dry... balbalbal... which make sense, but kind of impossible for me to do now due to the london weather... cloudy and rain.. i also have no idea how am i suppose to dust free a pebble dash wall...i mean what standard do i need to meet to be 'clean/ready to paint'.
     
  4. joinerjohn1

    joinerjohn1 Screwfix Select

    Some plaster sometimes looks like it hasn't dried properly. Only way to test if it's still wet is with a moisture meter.
    The render on the outside should waterproof the wall anyway. ;);)
     
  5. cl0391

    cl0391 New Member

    the case is, it is a kitchen area, i have plastered 4 walls, 3 dried completely. only one left wet... very big difference. that's why i am kind of believe the exterior wall is vulnerable to weather conditions.
    i am actually start getting worried if the wall doesn't dry in another week or 2, the plaster i put on will start falling off lol
     
  6. Is this a single skin wall?

    Really, if an exterior wall that's been rendered is letting in moisture from the outside, you have a problem that I don't think a bit of paint and/or waterproofer is going to properly cure. That wall should be waterproof in its own right.

    If it's a cavity wall, then you really have a problem.

    Ok, it could till be that that wall is a lot colder than the others, so your plaster is still drying out ok, but chust more slowly.

    But, if your plaster is still wet due to penetrating damp, you are in trouble.

    If this is the case, then I suspect you'll need to seal the inside properly, using tanking, or a membrane, and then overline it with insulated board.

    To paint a rendered surface, if it's dusty, brush it away with a stiff (non-wire!) brush until it ain't any more. If it's powdery, then a stiff brushing and a coat of stabiliser.

    Then the best quality paint you can get - I've heard pliolite (solvent-based) is the best, but don't know? - and follow the instructions.

    But if you needed to rely on paint to keep you dry, I think you are living on borrowed time...

    (Not trying to scare you or nuffink...)
     
    cl0391 likes this.
  7. In any case, I fear you can do nuffink about it in this wet weather.
     
  8. cl0391

    cl0391 New Member

    Devil you are the star, thank you for such detailed advice. I'll carry on my research on the direction you have point out. very helpful, thank you
     

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