Black mould... best way to treat?

[Stephen]

Hi

I have recently removed a wardrobe from a bedroom.

Behind it there are a few patches of black mould on emulsioned plasterboard with peeling emulsion.

I now have a dehumidifier. It appears a combination of poor ventilation, poor heating and excess humidity was the cause.

Clearly I need to remove the mould and peeled paint. Any recommended kits for killing & removing this mould off the plasterboard?

The room is going to be repainted. Can I buy additives to put into the new paint to prevent a recurrence of new fresh mould... Something silver or benzalkonium chloride?

TIA,

Stephen.

[Tim Watts]

On Friday 31 January 2014 10:02 Stephen wrote in uk.d-i-y:

Bleach is all it needs IME.

[Andrew Gabriel]

There's no point killing it - it would immediately return if the conditions are right again. You need to change the conditions. You can get paints with fungicides, but I think most people who give that a second thought decide they don't want to sleep and live with fungicide chemicals.

It's there because the wardrobe is providing significant thermal insulation, so the wall behind it is below room temperature, and below the dewpoint temperature, so condensation is forming. Ideally, you should insulate the wall, e.g. line the wall with thermal insulation which is sealed to prevent warm moist room air getting behind the insulation. If it's an unfilled cavity wall, consider filling it instead.

Alternatively, move the wardrobe so it's against internal walls, not external walls, although you would still benefit from thermal insulation on those external walls.

[Another John]

I had this behind a downstairs cupboard. I washed it off with a 10% bleach solution, until all was clean, then scrubbed the area again with the solution (not too hard, because it is wallpapered).

Let it all dry, repainted, and it hasn't returned.

However

(1) I haven't put the cupboard back in that position.

and much more significantly

(2) I discovered that the end of a small wall in the garden had fallen inwards, against the house wall, above the damp-proof course. (The cavity must also be bridged at that point I guess.) I put that right pretty quick.

John

[meow2222]

Clean it off, bleach to kill it. If it wont clean off 100% apply fungicide. ZnSO4 and aspirin are completely harmless. You'll need to stop that wall hitting the dewpoint or it'll recur.

NT