Section 707. Maximum Height of Buildings. — The maximum height and number of storeys of every building shall be dependent upon the character of occupancy and the type of construction as determined by the Secretary considering population density, building bulk, widths of streets and car parking requirements. The height shall be measured from the highest adjoining sidewalk or ground surface: Provided, that the height measured from the lowest adjoining surface shall not exceed such maximum height by more than 3.00 meters: Except, that towers, spires, and steeples, erected as part of a building and not used for habitation or storage are limited as to height only by structural design if completely of incombustible materials, or may extend not to exceed 6.00 meters above the height limits for each occupancy group if of combustible materials.