Excessive similarity to any other structure existing or for which a building permit has been issued or to any other structure included in the same permit application, facing upon the same or intersecting street and within 1,000 feet of the proposed site as measured along the center lines of streets in residential districts and within 500 feet of the proposed site in any district other than residential, in respect to one or more of the following features of exterior design or appearance: apparently identical front, side or other elevation visible from a street; substantially identical size and arrangement of either doors, windows, porticos or other openings or breaks in the elevation facing the street, including reverse arrangement; other significant identical features of design, including but not limited to material, roofline, height or other design elements, provided that a finding of excessive similarity shall not only state that such similarity exists but that it is of such a nature as to be reasonably expected to cause one or more of the harmful effects as described in § 376-100 of this chapter.