Is this mould coming through under the paint?

Discussion in 'Painters' Talk' started by ABCDEFGHIJKLNOPQRSTUVWXYZ, Nov 7, 2020.

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  1. Wondered whether I could get some advice - I live in rental property and have already told my landlord about there being some mould on the walls and said it looked like the mould was growing under the paint. He just fobbed me off and said no one had ever had damp issues before, which clearly isn't the case judging from some other parts of the house (e.g. rust on window locks from sitting condensation). He just told me to use a mild bleach and it would come off, even though I'd already tried that. I tried again anyway and it just doesn't come off, if anything it becomes darker because if you wipe enough some of the paint comes off revealing more mould! The first attached picture has got worse, but you can clearly see the brushstrokes over it, especially near the skirting board. The second attached picture is a new area I've noticed since informing my landlord and again, it's doesn't seem to be mould on the surface, it's just gradually getting darker underneath the paint.

    I feel stupid even asking this as I am sure this is just mould that has been painted over, or mould coming in from outside, but would someone be able to give a second opinion? I'm obviously worried about eventually losing some of my deposit and I'm a bit confused why my landlord wouldn't be more concerned about this (unless of course it was him who painted over it!). I leave windows open to air the property, have a dehumidifier, damp crystals etc. etc. to try and minimise any condensation, but I feel like it's a lost cause if it's already in the property/a structural issue.

    Thanks in advance.
     

    Attached Files:

  2. Wayners

    Wayners Screwfix Select

    That looks like surface mould from condensation.
    Wash with white vinegar and water 50/50 if memory serves. Bleach can damage paint. Buy vc175 paint additive or buy paint with a mould inhibitor in already and plenty about including matt emulsion.

    If you think you can have damp get a damp meter as cheap and test but normally paint will bubble up if rinsing damp
     
  3. Astramax

    Astramax Super Member

    Agree with above but will add historic surface condensation mould that has been painted over without treating first. You need to ventilate the property much more to allow a good flow of air. Probably an outside wall.
     
  4. Thanks for this, yes it is an outside wall. That confirms my suspicion that it is historic and been painted over - I will badger the landlord again. We are trying all we can ventilation wise, but obviously hard in winter to keep the balance between well ventilated and keeping warm!
     
  5. koolpc

    koolpc Super Member

    Dehumidifier a good idea for now.
     
  6. Astramax

    Astramax Super Member

    Don't dry washing over radiators as the water vapour will condensate on an exterior wall, treat the mould with household bleach 50/50 mix, apply to mould, leave for 30 minutes and wipe off then leave to dry.
     
  7. Bobby Dazzler

    Bobby Dazzler Active Member

    Using a dehumidifier and ventilation at the same time is pointless and expensive. You are trying to dehumidify the outside, and increasing your electric consumption with no effect. One or the other, not both.
    Ventilation only works with heating. Cool damp air coming in - being heated, thereby reducing the RH and allowing the air to 'collect' more moisture - then escaping to the outside taking the additional moisture with it. Repeat ad infinitum.
     
  8. Thanks for all the replies, this was more a question about whether this is untreated mould painted over by (I assume) previous tenants, rather than how to get rid of the mould itself. Seeing as it is under the paint, I imagine it would need stripping, treating, then repainting, but that's a decision for my landlord.
     
  9. Red Star Boats

    Red Star Boats Active Member

    BD
    You are correct regarding dehumidifiers not being used with excessive ventilation, however your assumption that cold air is damp and warm dry is I believe incorrect. Warm air actually holds more moisture than cold, the only effect heating has is to keep the temperature in the room above dew point, or the point at which the moisture in the condenses, this why condensation appears mainly on cold surfaces, windows, mirrors etc so ventilation and heating combined is the best way to combat condensation due to the relative humidity of a given space.
     

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