The provisions of this Part
2 do not require any changes or improvements to be made to lawfully existing structures. However, when an improvement is made to any existing structure, the provisions of § 17-14 shall apply.
The following provisions shall apply whenever
any improvement is made to an existing structure located within any
identified floodplain area:
A. No expansion or enlargement of an existing structure
shall be allowed within any one-hundred-year floodplain that would
cause any increase in the elevation of the one-hundred-year flood.
B. Any modification, alteration, reconstruction or improvement
of any kind to an existing structure to an extent or amount of 50%
or more of its market value shall constitute a substantial improvement
and shall be undertaken only in full compliance with the provisions
of this Part 2.
C. Any modification, alteration, reconstruction or improvement
of any kind to an existing structure to an extent or amount of less
than 50% of its market value shall be elevated and/or floodproofed
to the greatest extent possible.