Okla. Admin. Code § 120:10-1-6
Except as otherwise provided in this Chapter, no land shall be used and no building, structure or improvement shall be made, constructed, moved, altered, enlarged, or rebuilt which is designed, arranged, or intended to be used or maintained for any purpose or in any manner except in accordance with the requirements established in the zoning district in which the land, building, structure, or improvement is located, and in accordance with the provisions of this Chapter relating to any or all districts. The minimum yards and other open space requirements, including the intensity of use requirement, contained in this Chapter for each and every building existing at the time of the enactment of the regulations of this Chapter, or for any building constructed or structurally altered, shall not be encroached upon or be considered as yard or open space for any other building
Okla. Admin. Code § 120:10-1-6