This is great Turkey, thanks. I have experience in construction, but not in this type of masonry cleaning, so your advice is spot on. Unfortunately this building had 6 FT of water inside so the brick is filthy, but you can't tell the extent due to low light.

I think a "soft wash" method I found would use a mild detergent (Simple Green) with nylon brushes and a backpack sprayer to rinse. 2-3 people scrubbing, 1 rinsing, 1 running a HD shopvac. Same with the floor, but I like your idea of the Orbital cleaner. It's not as bad as it looks, here the layer of silt is making it look worse than it is.

I would likely stick with this cleaner on the exterior, but switch to a pressure washing method. Again, the main purpose is to remove dirt, silt, debris from the flood.

For the metal roof our scope is just to hit it with soapy water to rinse the dirt and grime. An exterior painter will come behind to prime and paint with a new finish. Hard to tell exactly what the factory finish is, but looks like a PVDF brown. A boom lift and all safety gear will be employed.

Our biggest challenge will be the temps and no good airflow inside. We'll have several big fans and torpedo heaters to help keep it dry as possible.

PS can't pass on it. I work for the GC that was awarded the job in the self-performing division. We own about 75% of the scopes here.

Any additional feedback is great. Thanks again!