Open space at rear

(1) Every person who shall erect a building shall provide in the rear of such building an opening space, exclusively belonging to such building, of not less than six lineal feet at every point along the rear of the building free from any erection thereon above the level of the ground. rear. (2) A person who shall make any alterations in or addition to such building shall not by such alteration or addition diminish 12 Public Health the aggregate extent of open space provided in pursuance of this By-law in connection with such building.