If
any non-conforming use or structure is destroyed by any means, including
flood, it shall not be reconstructed if the cost is more than fifty
percent (50%) of the market value of the structure before the damage
occurred unless reconstructed in conformity with the provisions of
this Chapter. This limitation does not include the cost of any alteration
to comply with existing State or local health, sanitary, building
or safety codes or regulations or the cost of any alteration of a
structure listed on the National Register of Historic Places or a
State Inventory of Historic Places.