How to deal with black mould on walls.

[richiep]

Hi all,

I'm wanting to tile my bathroom walls, but there are large amounts of black mould growing over the paint. I know the paint will need to be removed before i tile, but how big a problem is the mould?

I can wipe most surface mould off with tissue but is this mould in the plaster and will the walls need re-plastering? Or is there a way i can deal with this to enable me to tile over?

What i don't want is to tile the walls then find them popping off due to damp.

All advice would be grateful please.

Rich

 

[Gazzer]

Where is the mould coming from 1st ? No good cleaning it of and tiling if its coming through from somewhere else.

 

[diamondtiling]

Is there any ventilation in the bathroom, as in a wall vent?

If not then it wont help, as Sir Ramic says you need to find the cause.

 

[richiep]

There is no wall vent or extractor fan, just a window we open to air the room. The walls that have the mould are the exterior walls if that makes sense, ie, no room on the other side, just the exterior of the house. We have only this year had the walls insulated, had insulation blown in.

 

[Gazzer]

If you are happy that the mould is coming from being used as bathroom without ventilation then firstly I would install some sort of extractor fan for the future. The mould could be dealt with by cleaning down with bleach. I believe this will kill the mould spores.

 

[diamondtiling]

Insulation blown into the cavity? How old is the house?

Bricks get wet in the rain and dry out naturally, similar to grout. With the pumped in insulation the air cavity has gone and damp has no where to go so it is drawn to the driest area which will be the inner wall.
Dont confuse this with slabbed insulation that is fixed to the blockwork, at least with that system there is still an airway.

 

[Mouldy]

Blown insulation. One of the worst inventions ever I think........

 

[richiep]

If you are happy that the mould is coming from being used as bathroom without ventilation then firstly I would install some sort of extractor fan for the future. The mould could be dealt with by cleaning down with bleach. I believe this will kill the mould spores.

Thanks, i will try the bleach to see if it has an effect. Think the extractor fan is the way forward too. Much appreciated.

 

[2020Tiling]

could just be condesation ! have you a decent size radiator in the room ? as you need heat and ventalation to cure condensation. you could use bleach to get rid of the mold then use a diuhumidifier the take the moisture from the walls.

 

[Mouldy]

YOu could also try this:-

Zinsser UK - Perma-White (Interior) or this;

Zinsser UK - Bulls Eye 1-2-3