Red stain/algae

[passat]

Hi. If anyone has any advice or has ever encountered a problem with a reddish colour stain/algae on a concrete garden wall which is impossible to remove, have tried bleach etc; its in every concrete garden wall in our area.

Thank you

 

[gocall01]

Hi. If anyone has any advice or has ever encountered a problem with a reddish colour stain/algae on a concrete garden wall which is impossible to remove, have tried bleach etc; its in every concrete garden wall in our area.

Thank you

Are you my next door neighbour?
I have this issue too, I have no idea what has caused it.

I am going to power wash it in the coming days, I'll let you know how it goes.
I know the reddish colour will wash off but I am interested to see if it will come back!

 

[sydthebeat]

it is a common fungus that grows on unpainted concrete walls... it is more apparent in boggy or wet areas such as the midlands etc.... well i suppose all of ireland is 'wet' these days....

Simple powerwashing wont solve the problem... it will need chemical cleaning, like bleach. Then paint the wall.

It isnt harmful in any way... just unsightly...

 

[Teabag]

Tom Cruise had this problem in War of the Worlds.