Not a civil engineer, but I think different areas have very different considerations, and I'm not sure there is a 'normal' residential construction. A beach-side house in Florida probably has very different issues from a house built somewhere like Las Vegas. Salt, humidity, wind, earthquakes, soil, and other considerations vary.

> How often is your house dunked into seawater?

For people hit by hurricane Sandy the answer is at least once.

Over that long a time period it could be damaged just by rain - it's hard to say because corrosion tests aren't done with respect to a 1000 year operating life in mild conditions. I'm sure an expert could figure that out, but it would require looking at the corrosion rate of the specific steel, the exposure to any kind of forces that could damage the oxide layer (e.g. scratches), and the thickness of the member.

> How often is your house dunked into seawater?

Hopefully the house ain't in Florida. Or California's Central Valley.

Living near the ocean means that salt air corrosion will become a problem eventually. It eats away car bodies over time, for example.