What is this black staining on stone door canopy? How do I remove it??

Can anyone recommend any products they have used to successfully get rid of black staining on stone?

I think it's black mold and Google results tell me to use bleach and a scrubbing brush but I'm hesitant on using any bleach.

Any tips would be greatly appreciated!

 

"wet and forget"

but the problem seems to be that the little roof is damp because it does not have a suitable top layer. Maybe asphalt or lead. These days synthetic rubber membranes are used on flat roofs. Does water drip on it from a faulty gutter above? or from that hopper?

 

Thanks John, I'll look into that product.

You know what, I've never even looked at the top surface yet! Not long bought the house, but I will take a look. I doubt there will be any membrane of sorts though.

Yes, the guttering above is completely shot and rainwater drips over the edge all the way along the gutter. Do you think that that's the culprit?

 

might be blocked

yes.

 

The guttering is going to be replaced soon so hopefully if that's the cause, then it won't come back.

I'll give that Wet & Forget a go.

Do you think this product would be good for painting onto the top of the canopy roof? To act as a membrane

https://www.toolstation.com/thompso...dcRJXzOM1rAmnK55Xf46-PKccpmA3PzsaAjWFEALw_wcB

 

don't know, I'm not keen

Fixing the leak or overflow would be a better solution.