Every billboard must be so constructed as to leave an open space of at least 2-1/2 feet between the bottom of the display area and the ground. This open area may be filled with lattice work or other ornamental design which does not close off more than two-thirds of any square foot of such open area. Billboards constructed on properly on which there is a property established building line, must be built entirely in back of this building line; and no permit shall be issued for the construction of any billboard on any lot which is subject to a proper building line restriction, if the billboard is to be constructed in violation of the building line restriction.
('70 Code, § 11.8.6) Penalty, see § 153.99