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Insulation and render

Discussion in 'Building' started by beprepared, 14 Aug 2016.

  1. beprepared

    beprepared

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    I moved into a terraced property that had cavity wall insulation added a year before. We've started noticing some mould on that side of the wall. My initial thought is to have the insulation removed but the external brickwork also has render. The render also has some slight cracks around where the insulation was injected so I'm sure thats a contributing factor.

    I'm a little confused as to why if there's any reason to have a rendered brickwork and cavity wall insulation.

    I don't think both are necessary and would like resolve the mould problem as soon as possible. Whats the best course of action for this? Get a surveyor? Get the insulation removed? Get render removed / repaired?

    Any advice is appreciated.
     
  2. freddiemercurystwin

    freddiemercurystwin

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  3. beprepared

    beprepared

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    Well that's not really practical advice to get issue resolved. Can you elaborate as to why you would say that?
     
  4. vinn

    vinn

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    Why would a householder have cavity insulation installed 12 months before selling?
    When do you think the render was installed?

    Your question seems to be about possible damp/condensation effects of having c/i installed, and the state of the render?

    Interior and exterior photos would help?
     
  5. beprepared

    beprepared

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    I don't know why it was installed a year before but I still have the paperwork work for it.

    I don't know when the render was installed to be honest.

    Outside: https://www.dropbox.com/s/1corp95lyd6p6aj/outside-1.jpg?dl=0
    Outside: https://www.dropbox.com/s/hpb2s48uj45n5os/outside-2.jpg?dl=0
    Inside: https://www.dropbox.com/s/94g5g9hf94kyaj1/inside-1.jpg?dl=0
    Inside: https://www.dropbox.com/s/s6p7cotec1mfg77/inside-2.jpg?dl=0
     
  6. vinn

    vinn

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    Thanks for the photos.
    I can see some injection holes but no cracking around them. Can you, on site, see a pattern of injection holes?
    There are however, a number of minor hairline cracks on three walls.
    All the door/window openings lack drip hood mouldings above them.
    Rusting metal plant hanger.
    The rear elevation outside corner area shows signs of moisture retention - what kind of render is that?
    The decking is too high - its bridging your DPC.
    Splash marks can be seen above the decking.
    Are your internal floors solid or suspended?

    The interior behind the appliance shows condensation signs (and mould?).
    The other photo appears to show condensation signs.
     
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  8. beprepared

    beprepared

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    I can see atleast two on each side of the window, two below and there are more further down.

    That is something which I think could be a contributing factor but again something I need advice on.

    I don't know to be honest but it looks like its sand and cement.

    What is DPC? The decking was only recently added, a few months. The splash marks aren't from the decking. Moisture from the ground?

    I think they're suspended.

    The other photo did also have mould but I cleaned this a few days ago. Essentially both rooms have condensation / mould.

    What do you think is the best course of action to treat it all?

    Thanks again
     
  9. vinn

    vinn

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    The render could originally have been applied to cover signs of movement or bad brickwork
    Render should be stopped short of any ground contact - it should be stopped above the DPC using a BellCast bead.
    Render should never bridge any DPC.
    You could open up the fine cracks just enough to clear any debris, and then fill the cracks with cartridge injected Polyurethane.

    There should be airbricks ventilating below the suspended floors - these must not be blocked off.
    Have you been under & examined the joists under the floor?

    Whats to be done beyond what I've said above: I dont know because it could be that you have extremely cold walls with interior conditions favourable for condensation.
    Then again, it could be that moisture is bridging and penetrating your cavity fill to show as cold damp spots on the inside.
    The answers might be why was the render & cav fill was originally applied?

    You might need an Independent Damp surveyor to inspect.
    What did the mortgage survey say?
    You should research on here for all these issues.
     
    Last edited: 14 Aug 2016
  10. tomfe

    tomfe

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    Wait until it's raining then go outside and have a look at the guttering, that corner of you house looks like it gets very wet as it's stained.
     
  11. freddiemercurystwin

    freddiemercurystwin

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    Because it's a gamble if retrofit CW insulation will create problems internally or not, the installer won't give a **** and it's removal is nigh on impossible.
     
  12. ^woody^

    ^woody^

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    That looks like a typical Victorian terrace, and if it is it wont have cavities, so can't have cavity wall insulation.

    That damp pattern is typical condensation damp, not penterating damp. So read up on condensation prevention
     
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