Black stains on brick, any suggestions?

[markhop 14]

I am doing a 3 story 100 yr old brick house wash. All looks good except for black stains, about 2 feet wide and the full height of the house. These stains are only where the gutters (not aluminum) were at. High pressure directly on it does nothing, oxalic acid does nothing. Has anyone ran into this b4? How did you remove this? I think it is caused by the metal depositing on the brick over the years. Brick is very porous.

[Dan Stapleton 14]

I am doing a 3 story 100 yr old brick house wash. All looks good except for black stains, about 2 feet wide and the full height of the house. These stains are only where the gutters (not aluminum) were at. High pressure directly on it does nothing, oxalic acid does nothing. Has anyone ran into this b4? How did you remove this? I think it is caused by the metal depositing on the brick over the years. Brick is very porous.

Be careful using oxalic acid on brick. Try a butyl based degreaser (test spot). If you don't KNOW its not mildew try sodium hypochlorite. Do a search on brick restoration products.

[James 624]

It's Mold Comming From The Constant Moisture Provided By The Gutter.