Indiana Code Title 36. Local Government § 36-7-11-19

Sec. 19.  (a) In an ordinance approving the establishment of a historic district, a unit may provide that the establishment occur in two (2) phases.  Under the first phase, which lasts three (3) years from the date the ordinance is adopted, a certificate of appropriateness is required only for the activities described in section 10(1)(A), 10(1)(B), and 10(1)(D) of this chapter.  At the end of the first phase, the district becomes fully established, and, subject to subsection (b), a certificate of appropriateness must be issued by the commission before a permit may be issued for or work may begin on an activity described in section 10 of this chapter.

(b) The first phase described in subsection (a) continues and the second phase does not become effective if a majority of the property owners in the district object to the commission, in writing, to the requirement that certificates of appropriateness be issued for the activities described in section 10(1)(C), 10(2)(A), and 10(2)(B) of this chapter.  The objections must be received by the commission not earlier than one hundred eighty (180) days or later than sixty (60) days before the third anniversary of the adoption of the ordinance.