Helping an investor remodel a 6000 foot commercial building. Was a church for a while then a newspaper office. Has a block foundation that has a history of leaks. First lowered the grade around the building, then gutters were installed. Problem is about 50 to 60 % better than before. Painted with water sealing paint, but is not helping much. There is an approximate 12 X 12 block room with a staircase for an exit. That room has a flat roof, but has a new rubber roof on it. The leaking area is in the 12 X 12 room and about 20 feet on the wall right by the room. This end of the building is the lower end of the grade. There’s a few leaks on the walls of the staircase room, but otherwise all the leaks are right at the floor where the block wall meets the floor slab.
I’ve heard of people coming in and cutting a trench in the floor and installing drain tile and a sump. Appreciate any suggestions.