Stains on concrete

[tinpanalley]

(This is in France, suburbs of Paris)
We've moved into this building and in several places on the insides of our balcony we have this mould/moss/something staining and I'd like to know what can be done without a power washer to remove the stains. Any thoughts?

 

[Wayners]

Biocide wash.
Called a soft wash.
Patio magic is one brand I use but there are others

 

[tinpanalley]

Biocide wash.
Called a soft wash.
Patio magic is one brand I use but there are others

Wow, really? I thought there would be some kind of home recipe kind of cleaner. Is this a safe thing to use or does it require all kinds of kit and gear to apply?

 

[Wayners]

No.
Just follow application advice.
Gloves etc.
Depends how far you want to go covering yourself up.
Watch YouTube

 

[StephenOak]

For hard surfaces like this then something containing benzalkonium chloride (BAC) is fine, that includes Patio Magic (which I have used) and a number of other products. No idea what branded products are available in France. BAC is also known as alkyldimethylbenzylammonium chloride!

In the UK, the branded products are c. 7% BAC and you dilute it down to c. 2%, so it is not that strong. When using it I wear gloves and wash my hands afterwards. If you are worried you can wear a mask / goggles.

It is a very common product, albeit at lower concentrations. You'll find it is liquid soaps, antiseptic solutions, etc.