All persons engaged in the erection of any building upon any lot fronting upon any street, avenue or alley shall be entitled to the use of one-third of the street, avenue or alley along and in front of the building so in course of erection for the purpose of depositing thereon building material to be used in the building; provided, that persons so using the streets and alleys shall provide suitable passageways around the building material and keep the same fenced at points where foot passengers are wont to travel, and at night sufficient light shall be placed around the same to insure the safety of persons and teams upon the streets and alleys; also provided, that the use of the streets and alleys for building purposes aforesaid shall not extend to any one person for a longer period than four months except by order of the city manager, and also provided that the material shall be removed at any time when ordered by the city manager.