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Wall repair after water damage

Discussion in 'Plastering and Rendering' started by optimystery, 15 Apr 2017.

  1. optimystery

    optimystery

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    Hi,

    I am new to plastering but have done a few bits of DIY in the past successfully!

    Had a problem with damp that was fixed by a major roofing and repointing job around 6 months ago. It's definitely dry now, but when checking the blown plaster whole chunks of it fell away and left old crumbly/dusty exposed mortar. This pretty much distentgrated on contact to expose the bricks.

    My question is how to fix this? It's a small area and the surrounding bits seem pretty solid (see photos). What kind of render or concrete should I use to fill the hole before plastering?
    And what do I need to know about doing all the steps correctly so no cracks will occur?

    The pics show upper corner of wall adjacent to ceiling. As well as the hole there is a bit of paper and paint that flaked away. Can this be skimmed also?

    Many Thanks
     

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  3. Mottie

    Mottie

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    I'm no expert but I'd say hack off everything that's will come off easily, unibond the wall and replaster. First use bonding if browning (if that's what they still use these days) and then skim it with finishing plaster. No doubt I'll be told different!
     
  4. PrenticeBoyofDerry

    PrenticeBoyofDerry

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    As above, remove all loose flaky plaster. if the areas are only small, then probably best using a one coat/universal plaster. This can be applied as one coat or two if the areas are deep.
     
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  5. optimystery

    optimystery

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    Thanks for the replies. I was wondering if some kind of mortar would need to be used before plastering to fill the deepest parts of the hole (around 2-3cm)
    Maybe just 2-3 coats of plaster?
    Unibond is 1 part to 5 parts water according to the sticky on this site
     
  6. PrenticeBoyofDerry

    PrenticeBoyofDerry

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    If you have areas that are 3cm deep, then it would be advised to use a basecoat plaster (bonding plaster) or you could apply a basecoat using the one-coat type of plaster. it would depend on the amount work/area sq/m that would need to be done, to do basecoat and skim, you would need to purchased two plaster products, if using one-coat you only need the one product.
    With regard to application of PVA, you are best advised to read and follow the MI's of the particular brand you purchase.
     
  7. vinn

    vinn

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    The inside corner where the wall joins the ceiling doesn't seem to have been taped - and now there's been some slight movement thats opened the join up a little?

    You could choose to do nothing further with the large gaps at the wall meets wall inside corner
    , & simply pull it out with sand and cement and then skim it.

    However, the corner seems to have been repaired with a jumble of brick bats, and the old skim has not taken to the surrounding wall(s?).
    You seem to have skim finish over skim finish over a plaster background - the prep for the last, final skim was not prepped properly.

    External wall corners should bond & tie-in wall to wall.
    Are your your walls solid walls?
     
    Last edited: 17 Apr 2017
  8. optimystery

    optimystery

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    Many thanks. The height of the hole is about 50cm.
    @vinn I havent done any work on this, just loosened what was already there. These are external walls yes.
     
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  10. vinn

    vinn

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    No matter who attempted a repair - the result is rubbish. This is prior to any connection with roof leaks or duff pointing.
    Best practice is to take it all out from the "repaired" area, and set properly bonded-in bricks correctly laid in place.
    I know that they are external walls but I'm also presuming that the walls are solid?
     
  11. optimystery

    optimystery

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    There seems to be a bit of confusion there. The external repointing and roof repairs were done to a very high standard.
    What you see is 115 year old brick and mortar exposed after the original water damaged plaster fell away.
     
  12. vinn

    vinn

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    There's no confusion here.
    I made no value judgement on the roof & pointing repairs.

    I specifically referred to "prior to any connection with roof leaks etc" - indicating that repairs appeared to have taken place at that internal corner in the past before your other, later external difficulties.
     
  13. optimystery

    optimystery

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    No repairs have taken place yet, that's what I need to do :)
    That's just old wall revealed by fallen plaster
     
  14. vinn

    vinn

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    One last time:
    I never mentioned or implied that you had done the internal repairs - I merely noted that repairs had been carried out in that corner at an earlier unspecified date.
    When that date was I have no idea.
     
  15. Nige F

    Nige F

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    Just make it good with one coat as Prenticeboy has suggested.
     
    Last edited by a moderator: 17 Apr 2017
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