I am cleaning the exterior brick wall. The power wash takes away most of what appears to be a green algae. But close to the ground the stuff does not come off easily. There are also some brown stain on bricks and mortar. What are my options? Is it ok to use bleach? for bricks? for plants? What chemical do you recommend, if any. Does vinegar work?! The brick is just the usual type with salmon-color appearance.
Apparently a concern is too much reliance on pressure wash to clean the brick can create a problem. Claim is that water could get inside of wall and cause mold. So some folk recommend relying on chemical wash and less on pressure. I understand this can happen if I spray on a crack but does brick let water go through?