Mould behind lifting wallpaper

Discussion in 'Other Trades Talk' started by David Alsop, Jul 12, 2018.

  1. David Alsop

    David Alsop New Member

    I've recently bought and moved into the ground floor flat of an old (~1910) mid terrace.

    The living room is (mostly) wallpapered and painted. As we were preparing to repaint I noticed some areas where the paper was lifting from the wall and sort of cracking.

    I intended to remove the worst of the loose paper before applying a small amount of filler to even things out, but quickly found mouldy looking patches behind the paper, and quite an extensive amount of loose paper.

    So, before you know it, I'm faced with this:

    [​IMG]

    The black mould doesn't look great, but my pet theory is that it's probably largely historic, caused by a combination of condensation in that corner and the old wallpaper having been put up using paste without any fungicidal additives. The walls underneath aren't obviously damp, we've seen no sign of mould coming through the paper to the surface anywhere in the room, and it doesn't appear to have been painted desperately recently (as in an attempt to cover up the problem and get the place sold!)

    The flat edge towards the bottom left, for what it's worth, is where the previous owners had damp proofing installed, and this is an external corner.

    What kind of further remedial work are we looking at? Should we plan to remove all the wallpaper in this room, or might we reasonably expect to get away with just stripping the affected areas back?

    Can we do that safely ourselves to find the extent of the problem, or should we hire a professional with relevant experience at this early stage?

    If the plaster walls underneath the paper need anything more than a bit of a filler, are we looking at a re-skim of the whole room?
     
  2. Dr Bodgit

    Dr Bodgit Super Member

    The mould looks localised but I'd be keen to know where the damp has come from. That looks like an outside wall/corner so what's above it and outside there where water might have come in in the past?
     
  3. David Alsop

    David Alsop New Member

    Yes, it's an external wall. There's a drain in that outside corner, and a downpipe from the gutter, so a leaky or blocked gutter or downpipe could well have leaked water down that corner in the past, I suppose. A small patch of mould has been uncovered on the other side of the room, though, on another external wall, but well away from the drainpipe.

    Also, as I mentioned, there's a recently-added damp-proof course directly below the exposed portion in that picture. I would assume that was as a response to perceived rising damp, but given the height it has reached, that seems unlikely to be the cause for this.
     
  4. Dr Bodgit

    Dr Bodgit Super Member

    Mould is likely caused by historic leaking of that downpipe then, so assuming there is no more leaking, the mould shouldn't return.

    If you are going to paint the walls then I'd strip off all the wall paper and prepare thoroughly, that way you are sure all mould is removed, no damp patches or other nasties. If walls are rough then a reskim should make everything nice but then you have skirtings and architraves to contend with too. Might get away with filling and two coats of good quality lining paper.

    Try posting in the Painters section, Astra and the likes are the Pros there.
     
  5. Astramax

    Astramax Super Member

    What is directly above the damp, a bathroom, toilet any pipework?.
     
  6. David Alsop

    David Alsop New Member

    I'm not really sure - I haven't been in the upstairs flat. It's a kitchen / living room. There's some pipework that exits the room above in that general area, though I'm not sure what - perhaps kitchen sink waste pipe?

    [​IMG]
     
  7. Astramax

    Astramax Super Member

    If the wall is dry the mould could well be historic in that case kill the mould with a fungicidal wash or even household bleach, paint on over the mould with a paint brush, leave for a couple of hour's and wash off then leave to dry out thoroughly. When dry paint over the area using Zinsser Cover Stain, two coats would be fine. Hopefully you will be ready to proceed with the decorating once paint has dried.
     
  8. Dr Bodgit

    Dr Bodgit Super Member

    That pipe looks too high to be a sink waste, I reckon its a boiler condensate pipe, in a pipe.
     
  9. Astramax

    Astramax Super Member

    Is the mouldy area damp?
     
  10. David Alsop

    David Alsop New Member

    Yeah, the wall seems dry - we would obviously make sure of that before proceeding with decorating.
    I'm definitely inclined to think it's historic, but not sure how far to chase it back behind the rest of the wallpaper.

    When it comes to deocarting, any tips on achieving a smooth-ish transition between the remaining wallpaper and the now-exposed walls? I was anticipating filling a few cracks, re-pasting the edges of the paper, and maybe hoping a couple of coats of primer might hide the joins?!
     
  11. Astramax

    Astramax Super Member

    If it were me I would strip off the wallpaper starting from the window and go all the way along the other wall as well as that may need some attention, then make good where required, size wall let dry and re-line with 1400 grade lining paper or if you like a small challenge use WallRock Fibre Liner or WallRock Fibre Liner Plus.
     
  12. David Alsop

    David Alsop New Member

    Thanks all.

    Think we'll strip the rest of the paper first - masks and goggles in place just in case of further mould - then see if we might need to call on outside help to clean the mould away.

    Once that's done, lining paper probably makes a lot more sense for us than a re-skim. I'm not too confident in our paper-hanging skills, so might call someone else in for that too!
     
  13. Astramax

    Astramax Super Member

    What area are you?
     
  14. David Alsop

    David Alsop New Member

    West London
     
  15. Astramax

    Astramax Super Member

    Not near enough, Brighton area here! :(
     

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