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Damp / salt second opinion please.

Discussion in 'General DIY' started by paulandlaura, 20 Jan 2009.

  1. paulandlaura

    paulandlaura

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    Hi
    The paint is flaking off the wall and the wall appears damp as the paint looks darker in patches and even feels a bit damp.
    But, there is white powder forming in patches all over the area and I have been told this is not a damp issue but salt comming out of the wall. The chap also said the only way to really solve the probelem is take the plaster off and re-render with an anti salt addetive.
    Does this all sound satisfactory?
    Thanks
     
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  3. Bodgeit and scarper ltd

    Bodgeit and scarper ltd

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    I had that problem! I knocked a hole in the wall and fitted a window :eek:
     
  4. jj4091

    jj4091

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    Personally I would remove the paint, then try a fungicidal wash, or mild solution of bleach first of all & repaint. Also if it is happening behind an article of furniture, move the item away from the wall to allow ventilation.
     
  5. paulandlaura

    paulandlaura

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    Thanks JJ. That seems to be the advise elsewhere. Also I think I have stumbled upon article that seems to make sense regards the lack of ventilation under my suspended floors.
     
  6. PerryOne

    PerryOne

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    What you have is a damp wall.
    The wall is drying out and as it does so it brings salts to the surface.
    It may not look very nice but, it does no harm.
    However, you may care to investigate where the damp is coming from?
    Check things like leaking gutter, roof, pipes, cracks in wall, poor pointing, damp proof course to see where it comes from.
    Does it happen all year round or only in winter?
     
  7. paulandlaura

    paulandlaura

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    Thanks JJ
    It only seems to be a winter problem.
    This old damp issue seems to be a well debated issue. Its either rising or ventilation or another problem and some people are adamant, rising damp don't even exist.
    I have been told its not rising damp and there is no point injecting. These are chaps who walked away having earned nothing from us. So I can only assume its not rising damp. The walls seem wet. Its not a gutter or window.
    We have replasrtered within the last few years. Is this a problem in a 70 year old house?, also we have extended in 3 directions and I have read that there can be issues under suspended floors, if ventilation is less than adequate, which in the core and original part of the house it may now be?
    It may not be a big problem just a little unsightly, but then a little unsightly is a big problem if your my wife! ;)
     
  8. PerryOne

    PerryOne

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    OK, so you probably have the answer.
    Having eliminated all the usual suspects.
    We probably have a case of wind driven rain.
    Is this wall in an exposed position?
    What can happen, is that the wind blown rain hits the wall at the speed of a bullet and under constant wind pressure it is forced through the wall making it wet.
    Once the wall is wet, it becomes cold, as the wet wall will bring the cold into the room.
    Then the humidity in the home makes its way to the cold patch and condenses keeping it wet and cold.
    Once the summer comes, the wall dries out, until the following winter.
    The solution, if the pointing is in good condition and the wall looks OK, paint the outside of the wall with three coats of silicone paint, this will stop the rain from soaking into the wall, then over the course of the summer the wall will dry and the problem will go away.
    Don't expect an instant result, it will take some time for the damp to disappear.
     
  9. DIYnot Local

    DIYnot Local

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