A. No expansion or enlargement of an existing structure shall be allowed within any floodway area that would cause any increase in the elevation of the base flood elevation.

B. No expansion or enlargement of an existing structure shall be undertaken in the direction of the streambank.

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. Historic structures undergoing repair or rehabilitation that would constitute a substantial improvement as defined in this chapter must comply with all ordinance requirements that do not preclude the structure's continued designation as an historic structure. Documentation that a specific ordinance requirement will cause removal of the structure from the National Register of Historic Places or the State Inventory of Historic Places must be obtained by the Secretary of the Interior or the State Historic Preservation Officer. Any exemption from the ordinance requirements will be the minimum necessary to preserve the historic character and design of the structure.

E. Any modification, alteration, reconstruction, or improvement of any kind that meets the definition of "repetitive loss" shall be undertaken only in full compliance with the provisions of this chapter.

F. No expansion or enlargement of an existing structure shall be allowed within any AE Area/District with floodway that would, together with all other existing and anticipated development, increase the base flood elevation more than one foot at any point.

G. The above activity shall also address the requirements of the 34 Pa. Code, as amended, and the 2009 IBC and the 2009 IRC.