I would regularly clean stone Walls with cold water pressure washer. Works at 3000 psi on 20hp Honda Engine.. Its very powerful....
Not done a job like this before but would it remove then blackness in this stone in the picture attached?
How would you go about doing it.
My only concern is that it is on a main rd, busy road, with a public footpath below.
Has anyone done one similar and what's the best way? I was planning on getting up with cherry picker, spraying with hypo first and then blasting it.
Any other suggestions would be grateful
Thanks
Riz