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Do I need damp resistant plaster?

Discussion in 'Plastering and Rendering' started by Bens_Dad, 27 Aug 2018.

  1. Bens_Dad

    Bens_Dad

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    Hi folks,

    We've had a damp problem on the back of our 1930s house. Once the source of the damp is fixed, we can wait some time before redecorating (getting to this room is at least 6 months away!) and are planning to allow the wall to dry out before getting it re-plastered and then painting.

    The quotes I've had from damp specialists include using special damp resistant plaster. We obviously want to avoid any necessary cost so my questions are:
    • If the wall is dried out before we get it re-plastered, do we need to use damp resistant plaster? If so, why?
    • If not, can we dry things out with the existing plaster left on or need to strip it off to allow this?
    • If we do need a damp resistant plaster, is this something a general plasterer/decorator will be able to do or do we still need a damp specialist to do this?
    Appreciate your thoughts.
     
  2. bobasd

    bobasd

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    you hack off back to brick well beyond all damp signs - say the whole wall up to one metre from FFL.
    you best use a 3:1 or 4:1 sand an lime render mix.with a remedial finish skim.
    any plasterer can do it.

    is the wall an floor solid or what?
    is the outside rendered?
    is the ground level 150mm lower than the FFL or better 150mm below the DPC
     
  3. Bens_Dad

    Bens_Dad

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    Hi, thanks for replying. That's good news.

    To answer your questions:
    Solid walls with timber suspended floor
    The outside is pebble dashed (for the time being)

    Outside ground level is a raised patio roughly level with FFL ....

    the damp specialists that have looked at it have all said bridged DPC (which is what I originally thought) and so need chemical DPC and a French drain. However I've since managed to get under the floor with a damp meter and found that the brickwork below the DPC is drier than that above. So, conclusion at the moment is that water coming down the wall is soaking into brickwork rather than draining away.

    I'm planning to get a F drain put in with a waterproof paint on outside of the wall and see if moisture level reduces. If not then OK, chem DPC it is.
     
  4. bobasd

    bobasd

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    forget about chemical DPC's. hack off an use a sand an lime render.
    maybe a french drain properly dischargin somewhere will help.
    forget about waterproof paint to.

    carefuly check the condition of the timber joists an flooring and for any damp signs on the walls an skirtins.

    the wall was rendered an dashed could be because of previous damp issues. any cracks or failure in the render will increase dampness possibilty inside the house.
     
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  5. Bens_Dad

    Bens_Dad

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    Many thanks
     
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