The provisions of this chapter 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 § 242-30 shall apply.
Structures existing in any identified floodplain area prior to the enactment of this chapter may continue subject to the following provisions:
A.
No expansion or enlargement of an existing structure shall be allowed within any identified floodway that would cause any increase in the elevation of the 100-year flood.
B.
No expansion or enlargement of an existing structure shall be allowed within any FE area that would, together with all other existing and anticipated development, increase the 100-year-flood elevation more than one foot at any point.
C.
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 chapter.
D.
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.