A 1 foot piece of 6'' K-style gutter holds 2 gallons of water, during an extended rain event a one story 3,100sf house would dump thousands of gallons of water.
If I can find the time I'll run sizing on roof drains,,,,,4 inch roof drains are very common, on a flat roof....
And again, sounds like the people on site are starting to figure it all out,
Other than who's paying for it.
