4-104.A. Permitted Modification. A non-conforming building may be modified by addition or alteration only in a manner that does not change or that decreases the non-conformity. Ordinary maintenance and repair to non-conforming buildings may be performed without affecting the authorization to continue as a non-conforming building.

4-104.B. Prohibited Modification. A non-conforming building shall not be modified by any addition or alteration that increases the non-conformity.