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White stuff on chimney brickwork

Discussion in 'Building' started by mri_ice, 17 Mar 2020.

  1. mri_ice

    mri_ice

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    So sitting in the garden on the first decent day of late and noticed white stuff on the chimney brickwork. Quick google suggests efflorescence and advice seems to range from ignoring it to something being wrong with excess water and moisture that needs sorting out. A couple of things - chimney was fully rebuilt last year, i.e taken down to roof level and rebuilt with new lead tray and new lead work all around. New bricks used too. Now it has been absolutely biblical over the last couple of weeks and the amount of rain has been quite extreme. Is it likely “just” the recent weather that is to blame or do I have an issue that needs looking at? Really grateful for any input. Thanks - Martin
     

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  3. bobasd

    bobasd

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    its efflorescence and harmless but unsightly - it mostly appears roughly within your chimney re-build timescale. it often appears on previously wet brickwork.

    however, no flaunching can be seen on the top of the stack which might mean your stack brickwork is getting soaked in spite of any claims for a new lead tray?

    the flashing at the base of the stack is well wrong.
    given the stack appears to have been built into the ridge it might make for tricky flashing detail?

    get up and examine the chimney breast inside your loft for water stains or wetness.

    any signs of damaged decorations on the chimney breast on 1F or GF. or ceilings?
     
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  4. JohnD

    JohnD

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    You say the brickwork is newish.

    I've noticed several newish garden walls near me blooming over the last week or so. I think it must have been because a spell of dry sunny days set the brickwork drying out and drew the minerals to the surface after a long wet, dull spell. They were all facing open land and the afternoon sun.

    I've also seen it happen in winter when cold and frosty days have coincided with dry, sunny weather and very low humidity with drying winds.

    This was in a area of very hard water, and locally dug sand also quite limy.

    It'll probably weather away soon.

    I see your chimney seems to have plenty of leadwork, but looks quite untidily done. Did the builders seems skilled? My roofer uses a local lead specialist who does much neater work. Takes pics from the side that will how how it was cut in on the slope.

    if you can lay your hands on a pair of binoculars you will be able to see much better.
     
    Last edited: 17 Mar 2020
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  5. ^woody^

    ^woody^

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    Has thay been built exactly the same as it was?

    It looks a poor design that would, or is, allowing rain water to penetrate the stack from the top and thus saturate the bricks - which is the prime cause of efflorescence.
     
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  7. noseall

    noseall

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    It's efflorescence season folks!
     
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  8. mri_ice

    mri_ice

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    Thank you all, all replies much appreciated.

    Hmmm...local roofing company who came highly rated, were very uncomplimentary of previous lead work and quite convinced of their quality of work. Is there anything in particular that stands out as untidy? I'll attach some more photos of when when chimney was built.

    That was just the angle the photo was taken at. I can confirm there is flaunching on top of the chimney.

    That is concerning. Wrong how?

    Not any more. We had water coming in around the chimney before the rebuild, we had the roof done and the chimney with it.

    Erm, yes, I believe it was rebuilt 1:1.

    I have attached a few photos which I took during the rebuild.
     

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  9. bobasd

    bobasd

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    the lead tray is first class.

    from the angle of the photo flaunching should be seen .
    the recess near the top of the stack has a ledge that might hold water.
    flaunching should project from the face of the brickwork on a projecting undercloak, just like a verge undercloak, & for the same reasons - to throw water away from the brickwork.

    for your kind of tiles: the one piece step & cover flashing on the cheeks of the stack should have been done in two pieces of step-flashing and soakers.

    the step & cover flashing should have come down over the front apron flashing - not behind it.

    you have two apron flashings?
    it appears that a few tiles have been removed - which might allow water to enter "sideways" under the adjacent tiles?
    soakers go under tiles not aprons.

    the apron piece has been badly bossed into shape, & in time might split at the creases.
     
  10. ^woody^

    ^woody^

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    Yes, but with new bricks (ie renewed not rebuilt) and that would be why saturated bricks would leech salts.
     
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