"Substantial improvement" means any reconstruction, rehabilitation, repair, addition
or modification, or other proposed new development of a structure, the cost of which
equals or exceeds fifty percent of the market value of the structure before the start
of construction of the improvement. This term includes structures which have incurred
substantial damage, regardless of the actual repair work performed. The term does
not, however, include either, (A) any project for improvement of a structure to correct
existing violations or state or local health, sanitary, or safety code specifications
which have been identified by the local code enforcement official and which are the
minimum necessary to assure safe living conditions; or (B) any alteration of a historic
structure, provided that the alteration will not preclude the structure's continued
designation as a historic structure.
