Black mould on wall

Discussion in 'Just Talk' started by fillyboy, Oct 13, 2018.

  1. fillyboy

    fillyboy Well-Known Member

    I've got to decorate a room before Christmas where the owner has had issues with black mould on one wall, the room isn't used regularly as kids have flown the nest but she likes to keep it in good order and will during the winter months use a dehumidifier regularly.
    It's an upstairs room and the wall in question is on the elevation that tends to catch the 'weather', construction is solid wall, granite, I'm happy that it's not penetrating damp but is a condensation problem.

    Now, what I've suggested is 1" timber battens at 60cm centres, 25mm celotex in between, plasterboard over and skim.

    I've seen that wallrock do a thermal paper (polystyrene) which they recommend is papered over with standard wallrock.
    From looking at wallrock's site, this could be a viable and cheaper option, However, I recall as a youngster my old man putting up polystyrene wallpaper and painting it (I'm going back to the 60's here) and I can vividly recall taking a strange satisfaction from pressing the surface with my finger to make small 'dents' before eventually progressing to making full 'handprints'.

    Does anyone know if the new stuff is still as fragile as the stuff my old man put up in the 60's, I'm guessing that it will still be fragile in that if you knock it with a piece of furniture, it will easily tear.

    Anyone have any experience with it?
  2. retiredsparks

    retiredsparks Well-Known Member

    Have used old style poly stuff....pain in the arris unless on flat wall.
    Seems to help but even that that wont stop mould.
    What's needed is air circulation and keeping moisture levels sensible (cooking etc)
  3. Wayners

    Wayners Well-Known Member

    There are anti mould paints. Johnstones sell them so contact technical department for advise . You can also buy vc175 anti mould additive that I always carry on van. Condensation is a big problem for some and wallrock and thermal liners work well.
  4. goldenboy

    goldenboy Well-Known Member

    Usually its one of 5 things I find that cause mould if its not an external factor that is the problem.

    Radiator down to zero all the way through the winter.

    Drying clothes inside.

    Not cracking the window open.

    Loft insulation not installed all the way into eaves causing cold spots on ceiling perimeter.

    Wardrobes, bedside cabinets, bookshelves etc close to external wall causing an area of dead damp air.
    koolpc likes this.
  5. fillyboy

    fillyboy Well-Known Member

    Most of the above, wardrobe against wall, no central heating, the wardrobe will be going as no longer required..
    They do have a few storage heaters that are probably only used if it snows. A log burner in the lounge and an oil fired aga downstairs running 24/7 provide residual heat, they're not into being hot and they do like to open windows to let some air in.
    I've printed off details of the wallrock for them but hadn't thought about an anti mould additive, I'll check that out, thanks.
  6. Astramax

    Astramax Well-Known Member

    WallRock Thermal Liner is not polystyrene it's looks like fabric and is around 3mm thick and bluddy tough unlike polystyrene which falls apart just looking at it, I've used WallRock Thermal Liner several times over recent years and it takes a bit of mastering especially when cutting, you will also have to use the dedicated thermal liner adhesive. Also had a similar problem with a complete wall covered in black mould in a bedroom ....cleaned it off with Flash then treated the wall with a mould killer spray and after letting it soak for a couple of hours washed it off. I painted the wall with Dulux Mouldshield which has done an excellent job with no mould returning after 4 years so far, I know this is true recently went back and decorated the lounge. Also have used Crown Steracryl which is just as good and a little kinder on the pocket, both products cover very well and last.
    Last edited: Oct 13, 2018
    retiredsparks, fillyboy and Jord86 like this.
  7. fillyboy

    fillyboy Well-Known Member

    Thanks Astra, that's reassuring, it's not like they've got little kids running round but I'd feel bad recommending something like this and it got damaged just by looking at it.

    Another question if I can, the offending wall is just a straight wall but if they decided to do both external walls, the 2nd wall has a window, can this stuff be folded around a corner into the window reveal, or would it have to be cut on the corner, also you say cutting is fiddly, my normal approach is stick to wall with slight overlap, then straight edge and craft knife changing blade every few cuts, will this method work or does it need a different approach.
  8. fillyboy

    fillyboy Well-Known Member

    Edit, says on their website doesn't fold round corners, or at least they don't recommend it.
  9. DIYDave.

    DIYDave. Well-Known Member

    I’ve used the Wallrock thermal liner, luckily just on one flat, external wall, no window reveals

    Yep, no way will it fold around corners, you would have to cut at window and paper reveals seperatly

    The thermal liner is then papered over with lining paper, I used 1400 grade

    So if the cuts around the window are a little messy, the lining paper should tidy this up and give a crisp 90 angle

    As Astra says, this stuff is nothing like the thin polystyrene roll, it’s more like a fluffy, dense flock with a smooth, tough face layer bonded over

    Yes it will dent if knocked, not as easily as polystyrene but can be marked

    Wall now feels lovely and warm and no condensation/mould issues

    Just worries me where all that moisture ladden air has traveled to now, seeking out the next ‘cold spot’ to make its home :eek:
  10. koolpc

    koolpc Well-Known Member

    Surely a decent dehumidifier shoukd stop the mould? It did for us
  11. LEH

    LEH Active Member

    Zinsser Perma White may be worth a look too, available from SF or the other place...
  12. goldenboy

    goldenboy Well-Known Member

    One great trick for very cold rooms if you are putting fitted wardrobes etc in is to slide 25mm kingspan behind/down the side of the cabinets on the outside walls, or above if its a flat roof or very cold loft.

    Makes a huge difference to clothes getting damp or mildew.
    Jord86 likes this.
  13. Astramax

    Astramax Well-Known Member

    WallRock recommend to line over the Thermal Liner with WallRock Fibre Liner as this is by far a tougher product than ordinary paper lining paper. Video available to view on YouTube.
  14. koolpc

    koolpc Well-Known Member

    Dynamite the house. Rebuild
    Odd Bodkin likes this.
  15. fillyboy

    fillyboy Well-Known Member

    Already been done. If the Jerries still had bombs left over after Plymouth, they would do a wide turn back over Cornwall and drop at random coastal sites, this house is close to a railway line and a random Jerry bomb took the roof off, a gable end and parts of other walls, it was eventually rebuilt after the war. Coincidentally, it's the gable end that was destroyed that has the problem.
  16. Richard_

    Richard_ Active Member

    Possibly rebuilt with poor quality materials after the war, or perhaps a shortage of skilled builders?
  17. Astramax

    Astramax Well-Known Member

    Filly, Toolstation have reduced WallRock Thermal Liner from £ £37.60 per roll, quite a saving.
  18. fillyboy

    fillyboy Well-Known Member

    That is a good saving, thanks for the heads up. Funnily enough, a sample of it arrived from 'wallpaper direct' today, not the 3mm one but the 1mm as they wouldn't offer samples on the 3mm.
    I'm quite impressed with it, even the 1mm looks like it would provide a good thermal break and some degree of insulation, and like you said, it's nothing like the old polystyrene.
    I probably wont be doing that room till after Christmas but now they're thinking about losing an old iron fireplace on that wall, so might end up being battened and boarded after all.
  19. DavidDavidson

    DavidDavidson Member

    Oh how I love dynamite
    There once was a young lady named Alice
    Who used a half stick as a phallus
    They found her vagina in north North Carolina
    And her **** on a roof down in Dallas.
    Odd Bodkin and chippie244 like this.

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