Sub floor mould

[morton873]

Hi there, I was looking for some advice on a project I’m working on. I’ve lifted some of the floorboards up in our living room to insulate between the joists (1930s semi detached). However, we found a fair bit of standing water under there, which is due to an overflowing drain that is being fixed.

The sub floor is compressed soil but now it’s dried out we’ve noticed a fair bit of what I think are white mould spots, photos attached. The question I had is whether anyone had seen this before and is it safe? I want to clear out all the old debris to improve airflow before putting the insulation down, but don’t want to risk disturbing what might be mould if I do so. Part of me thinks it’s worth getting someone in to try and remove it, but not sure if that’s overkill?
Thanks in advance for any advice.

 

[Scally-Ho]

White mould can be just as dangerous as black mould. If that was my subfloor, I'd spray with something along the lines of Jeys Fluid suitably diluted for house use.

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[Scally-Ho]

@Morton873 If you have fish tank(s) in the house, remove to another location before spraying any kind of mould control.

 

[morton873]

Thanks @Scally-Ho, luckily no fish tanks or any pets to worry about. Closed the door to the room for now until we can get it sorted

 

[ree]

OP,
Its not mould - its simply salts left behind as the mud dried. Perfectly safe.

 

[morton873]

Hi @ree, I’d heard you’d normally get something like that on brickwork as it dries out (and seen it in places), I hadn’t realised it could also be true for soil. Can i ask what makes you think it’s that and not mould? Thanks.

 

[noseall]

Hi there, I was looking for some advice on a project I’m working on. I’ve lifted some of the floorboards up in our living room to insulate between the joists (1930s semi detached). However, we found a fair bit of standing water under there, which is due to an overflowing drain that is being fixed.

The sub floor is compressed soil but now it’s dried out we’ve noticed a fair bit of what I think are white mould spots, photos attached. The question I had is whether anyone had seen this before and is it safe? I want to clear out all the old debris to improve airflow before putting the insulation down, but don’t want to risk disturbing what might be mould if I do so. Part of me thinks it’s worth getting someone in to try and remove it, but not sure if that’s overkill?
Thanks in advance for any advice.

The timber looks healthy. Ignore the debris on the floor.