The Board of Supervisors has the power and duty to certify to the appropriateness of the erection, reconstruction, Alteration, restoration, demolition or razing of any Building, in whole or in part, within the Historic Overlay District. The Board of Supervisors shall consider the appropriateness of exterior architectural features and signage that can be seen from a Public Street or way, only, and shall consider the general design, arrangement, texture, material and color of the Building or Structure and the relation of such factors to similar features of Buildings and Structures in the district. No permit for any such building changes may be issued until a Certificate of Appropriateness has been issued by the Board of Supervisors, pursuant to 53 P.S. § 8004.