Intent of the Historic Preservation Ordinance. It is the intent of this section to establish the circumstances, conditions and procedures to obtain a Certificate of Appropriateness, as hereinafter defined, from the Planning Board as it pertains to exterior architectural features, applications for permits from the Construction Official or applications for development of properties in the "District." No building permit, where such is required, shall be issued unless a Certificate of Appropriateness shall have been previously issued by the Planning Board, pursuant to this section, except in the case of an ordinary repair, emergency repair or where no change to a major architectural element is proposed.