Doesn't salt water erode concrete?

[Sarpedon]

Again, it is what a thing is designed for. A boat will use a variety of methods to keep the water out, to alleviate dampness from the water coming in, and properly ventilate and prevent growth of molds. Most houseboats are quite well ventilated, with windows on all sides. A large office building, mechanically ventilated, with its airhandling units mostly in the basement, would first suffer a failure of its ventilation system as water rises, then the damp will inevitably rise through the ducts into the core part of the building. Elevator shafts will have their bottoms filled with water, as their sump pumps are overwhelmed (these pumps are designed for occasional deluges, not continuous immersion), and become conduits for wet and mold.