No space which for the purpose of a building has been counted or calculated as part of a side yard, rear yard, front yard, or other open space required by this Ordinance may, by reason of change in ownership or otherwise, be counted or calculated to satisfy or comply with a yard or other open space requirement of or for any other building. The minimum yards or other open spaces, including lot area per family or percentage of lot coverage required by this Ordinance for each and every building existing at the time of passage of this Ordinance or for any building hereafter erected, shall not be encroached upon or considered as yard or open space requirements for any other building.