(Let me make it clear I am in Virginia so local laws may vary so be sure to check your state and local laws do not take this as concrete advice.

By the time potential renters see the units they have basically made up their mind.This is why, when passive investors look for a value-add deal, they should prefer the slightly junky building to the polished complex.There is some “meat left on the bone” to do an obvious improvement and quickly boost the rents.Full Article on this topic 👇👇👇Make Or Break Your Rents In Multifamily Deals

Concrete work is expensive. 

We cleaned the concrete floors with dawn and water and a stiff push broom for scrubbing.

Concrete work?

Is this a concrete structure?

The more concrete information you can get, the better analysis you can perform. 

They jackhammer the concrete on the perimeter floor, then excavate so that there is a downward slope going toward the sump pump all the way around.

It sucks air from below the concrete or from a crawlspace.

For reference the property is around 30 years old and located in the GTA, Ontario, Canada(an idea of build quality).Advice would be great because a structural engineer would come out to be very pricey especially if it wasnt needed.Photos:also the concrete at the bottom is completley untouched and no interior damage.