No structure shall be erected, moved, structurally altered, rebuilt, added to or enlarged, nor shall any land be designed or used, for any purpose other than as permitted in each zone by this chapter. No open space or yard surrounding any building shall be encroached upon or reduced in any manner except in conformity with the yard, lot area, building location, percentage of lot coverage and other requirements hereinafter designated for the zone in which the building or open space is located.