Black Mold Under Wallpaper

[DIY67]

I am removing painted wallpaper from a cold outside facing wall in the bedroom. I have had issues with condensation on the surface of the paper resulting in white mold in the corner (which has reduced dramatically since I applied Stormdry on the outside) . I am in the process of removing this paper to the plaster to hang thermal lining paper stuck with Wallrock thermal paste which prevents mold. I now have a dehumidifier in the room to dry out the wall before hanging the paper (4mm polystyrene backing) When the wall is completely dry, can I just apply the mold resistant paste without cleaning it as it seems embedded in the plaster. the plaster is still sound with no issues of it falling away. I want to avoid disturbing the mold if I can.

Thanks.

 

[Wayners]

Could be lime plaster and paper or emulsion over paper trapping moisture causing mould.
Let the wall breath.

 

[DIY67]

Ok, thanks. I have run the dehumidifier all night and will apply the thermal paste and thermal paper.

 

[^woody^]

Thats a classic shape and location for condensation mould not penetrating dampness. Normally this is unrelated to any external moisture penetration so your external application may be having a placebo.

You need to brush the mould off and treat the area plus 500mm or so with a quality fungicidal wash following the instructions. Plus the woodwork and floor or carpet. Then use a quality paste with fungicide in it if you are papering.

And look at the reasons mould was there in the first place and deal with that.

 

[DIY67]

It will be condensation for sure but the Stormdry certainly won't do any harm keeping external moisture out, especially on the spalled bricks. It's also an extra protection against the cold as wet bricks allow the walls to get colder. Its a solid wall as the house was built in 1883.

As for the mold, wouldn't normal shop bought mold killer do the job before I apply the paste ? I say that because Wallrock thermal paste "prevents mould, yeast and fungal growth" ?

 

[^woody^]

I don't know whether the stuff you get to spray the bathroom tiles or suchlike has the same strength, penetration or longevity as the stuff designed to soak into the plaster. It might, it might just be a marketing con, but who knows? Definitely don't use bleach though, that's ultra-temporary.

 

[DIY67]

My thinking was that the anti mould thermal paste coupled with the application of the Erfurt 4mm Insulated lining paper would suffocate the mould, but a good clean with some kind of decent killer sounds like a sensible option. A set of drawers sits in front of that area which I believe adds to the moisture. A dehumidifier is helping though.

Much appreciated.

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