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Rendered external wall insulation too weak

Discussion in 'Plastering and Rendering' started by zanc, 20 Dec 2020.

  1. zanc

    zanc

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    A few years ago we had, through a local government grant, external wall insulation fitted. Recently we had some work to be done and a ladder placed against the wall pierced the render. The roofer doing this work said that the rendered wall should take the force of a ladder against it and that the render was not thick enough and not fit for purpose. Is he trying to get out of the damage done or could it be that the rendering was poor. The company was approved to do the work by the local authority.
     
    Last edited: 20 Dec 2020
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  3. he’s right.
     
  4. zanc

    zanc

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    Thanks. All I need to do now is find a way of getting the EWI fitters to correct their poor work. I’m sure they will deny any responsibility. My first tack may be to approach the local council who approved the fitters.
     
  5. JP_

    JP_

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    I have thought about putting a little EWI where internal is not really possible - do people just render straight onto the insulation? I assumed some sort of board would be applied over it first? The area I plan to do is just a porch area that is protected from the weather, so if I can just stick insulation to the wall and render with a thin coat I will!
     
  6. it has to be pinned to the wall with the correct fixings , dependent on the substrate, and mesh bedded in to a scratch coat over the insulation , generally.
     
  7. JP_

    JP_

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  8. the ewi itself is strong enough to withstand a ladder. sounds like they may have left a gap , creating a void behind the plaster.
     
  9. zanc

    zanc

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    This is what has been done. It’s an approved EWI system that was used. I would like to understand what could have gone wrong for it to be penetrated by a ladder. Bad workmanship? Looking at the damage there appears to be a small space/gap between the render and the actual insulation
     
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  11. JohnD

    JohnD

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    No doubt there are different ways of doing it, but in Switzerland I saw it being done with rigid foam boards with a layer of cement board seemingly factory-bonded to it. The fixings were drilled through into the wall and a thin render applied over the cement boards.
     
  12. hard to say. there’s obviously a void or gap for the ladder to go through.
     
  13. JP_

    JP_

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    Somebody here mentioned these before, just found them again

    https://www.insulationexpress.co.uk/marmox-multi-board
     
  14. JP_

    JP_

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  15. JP_

    JP_

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    in fact, might get same boards for my next bathroom refurb - rather than do the usual kingspan + plasterboard / hardiebacker, just put these up and tile / skim.
     
  16. zanc

    zanc

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    If you don’t mind, can I ask your qualifications for that statement. I ask this as I would like to take the matter further and need some confidence to start the process. Thanks.
     
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