# Forum Home Renovation Sub Flooring  How to clean up mould under a house?

## MartinBob

Hi, 
We've discovered mould in a corner of under the house. It's on concrete stumps, and there are no signs of a leak above. 
Should we contact professional mould removers/cleaners? Or can it be cleaned up by the average home owner? Should I remove the top layer of dirt and spray the walls with vinegar, or am I wasting my time? More to the point, can it be resolved and removed permanently?   
Cheers, 
Martin

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## Marc

Try hitting it with benzalkonium chloride, Wet and forget or 30 seconds

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## joynz

What is the ventilation like underneath the house?   
No no point in getting rid of the mould if it comes back?

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## MartinBob

> What is the ventilation like underneath the house?   
> No no point in getting rid of the mould if it comes back?

  Under the house has standard air vents. Some look a little blocked by the beams holding the floor up.  :Frown:

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## MartinBob

> Try hitting it with benzalkonium chloride, Wet and forget or 30 seconds

  
Thanks for the starting tips.

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## joynz

Be sure to wear a p2 mask when you are near the mould.

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## Bigboboz

> Under the house has standard air vents. Some look a little blocked by the beams holding the floor up.

  Yeah that's my setup with the vents, behind the bearers. I think the vents do a 'better' job ventilating my house of it's warmth in winter than circulating the air under the house.  I had one bearer cut and put an exhaust fan to the vent and ran some ducts to the other two rooms.  I have also put in some slotted PVC on the outside of the foundations right down to their footings to take away moisture.   
This was done about a year ago, it's probably time to go down and see what it's like now but not a fan of crawling in confined spaces! 
We had a lot of moisture but the mould wasn't as bad as that!  Previous owners had used under the house as a dumping area for building waste when they did a 60s 'renovation', would have stopped a lot of evaporation.

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## METRIX

Need to address proper ventilation to stop it coming back in the future, depending on the design of the house , you may need to implement forced ventilation.

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## SirMe

> Hi, 
> We've discovered mould in a corner of under the house. It's on concrete stumps, and there are no signs of a leak above. 
> Should we contact professional mould removers/cleaners? Or can it be cleaned up by the average home owner? Should I remove the top layer of dirt and spray the walls with vinegar, or am I wasting my time? More to the point, can it be resolved and removed permanently?   
> Cheers, 
> Martin

  How did you go fixing and find ing the cause?

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## Oldsaltoz

Hi Mark,
I have found that Wet and Forget only works properly if exposed to rain after application.

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## Oldsaltoz

Ventilation, ventilation, ventilation. By far the best resolution. Also limit materials that may retain moisture. 
Good luck and fair winds. :Smilie:

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## Marc

> Hi Mark,
> I have found that Wet and Forget only works properly if exposed to rain after application.

  You can't be serious ...

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## Whitey66

Pool Chlorine and water, 50/50 mix and spray on with a garden sprayer. You can also use bleach.
Be very careful doing this, like anything else with chemicals - Full PPE. 
Get some ventilation under there.

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## mudbrick

Bathroom mould killer spray is good, it's a combination of bleach and sodium hydroxide.
Some Pool chemicals are good if you know what you are doing with chemicals. You wouldn't want to 
spray too much chlorine under a house and end up gassing yourself.

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## Oldsaltoz

> You can't be serious ...

  Dead serious, the dead and dying mold will stay looking dirty if not washed off.

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## Marc

Oh I see ... in order to look clean. Sure, but the mold is dead, that is the main thing. By the way chlorine bleaches the mold but does not kill it, and the water content in bleach actually feeds the mold. CHLORINE BLEACH IS NOT EFFECTIVE IN KILLING MOLD

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## phild01

Vinegar is a cheap mould killer. I would do that first.

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## DavoSyd

> Vinegar is a cheap mould killer. I would do that first.

  and do it hardcore:  Vinegar Concentrate Cleaner - 5 Litres 
(and don't forget why it is a killer - it is ACID...)

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## Marc

And you can use it to dress your salad too!  :Smilie:

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## phild01

> and do it hardcore:  Vinegar Concentrate Cleaner - 5 Litres 
> (and don't forget why it is a killer - it is ACID...)

  Never heard of concentrated vinegar but for that price you could get about 50 litres of the no brand stuff. Generally recommended to be mixed 80% with 20% water.

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