Sec. 4. LIMITATION ON ISSUANCE OF BUILDING PERMIT. No permit shall be issued by the City of Galveston for the construction of any structure in the Old Galveston Quarter or the reconstruction, alteration or demolition of any structure now or hereafter in said Quarter, except in cases excluded by this Act, unless the application for such permit shall bear a certificate under Section 6 of this Act that no exterior architectural feature is involved or shall be accompanied by a certificate of appropriateness issued under this Act, or in the case of the demolition of a structure, a certificate under this Act that thirty (30) days or such lesser period as the Commission may have determined has expired after receipt by the Commission of notice of demolition.