Plaster after a DPC

Discussion in 'Builders' Talk' started by Elisa, Sep 6, 2009.

  1. Elisa

    Elisa New Member

    Hi all,

    I had a DPC done about 3 weeks ago in all downstairs rooms after I moved in a house that smelled badly of damp and had tidal waves on the walls. The guys that did the job removed the old plaster, down to the brickwork and told me the old plaster that was there wasn't right (wrong mix or something) and so they did the DPC, replastered (with the right mix) and skimmed the wall. It's been finished to a high standard and I'm happy with the results. The smell has now gone, which is great.
    They told me to not decorate for 6 months because although the DPC would start working immediately, the moisture needs to get out of the walls and the paint/wallpaper wouldn't stick and it would invalidate my 30-year warranty. That's fair enough. What I have noticed though is that on some walls (admittedly on very small areas) there is a little bit of white fluff on the plaster. Is this efflorescence (i.e. bad) or is it a sign that the brick is drying out (i.e good). To be honest you have to look very closely to notice the white fluff, I have brushed it off and monitoring to see if it comes back. So I'd like your opinion on whether this is anything to worry about.

  2. Removed 4

    Removed 4 New Member

    Once the defective plaster has been hacked off, it's very much a waiting game for the brickwork to dry out properly. This can take between two to four weeks depending on the severity of the damp and the ventilation of the room in-between times.

    Some contractors become a little impatient, and want to finish the work prematurely before the brickwork has dried properly.

    Don't paint the new plaster whilst that fluffy stuff is still in evidence....

  3. Elisa

    Elisa New Member

    Thanks for that Lucia, I was going to wait the full 6 months anyway, I have the room upstairs to re-decorate in the meantime so I'm not in a rush.
    Cheers for the advice.
  4. house and home

    house and home New Member

    there are some paints that you can use that still allow the wall to "breathe" so will dry out even though painted! they are usually only matt in finish, but I have seen a couple which are classed as silk but.....arent as shiny as most silks!,

    Not sure though about the ramifications of painting over the hydro salts! seem to remember that these actually atract moisture and need a salt wash to remove them.....not sure though so pop down to your local "reputable" paint company (not b and q)...a decent one that knows what they are on about! they will advise you a lot better!
  5. joinerjohn

    joinerjohn New Member

    Elisa, yes it is effloressence. This is caused by salts in the brickwork coming out as it dries. Shouldn't be a problem though. I'd probably leave the bare plaster the 6 months so you don't invalidate any warranty. before you panit it just brush off the efflorescence.
  6. Elisa

    Elisa New Member

    Great, thanks all for your advice.
  7. 12benny

    12benny New Member

    old plaster should have been hacked off to a height of one metre. You dont re-plaster unless its a specialist remedial plaster such as Limelite. You render with sand and cement and lime, and skim finish with eg. Limelite skim or a board finish.
    Typically, render does not allow effloresence to show.
    If you had a written contract and /or warranty check what the specification was for hack-off and render.
    No Carlite Browning should come near the job.

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