This article applies only to building and nonbuilding uses in existence on the effective date of this code. Except as otherwise expressly provided in §
9.3, the lawful use of any premises existing on the effective date of this code may be continued although neither such use nor the bulk of the same conforms to the regulations.
Normal maintenance and repair, structural alteration in and
moving, reconstruction or enlargement of a building with nonconforming
bulk is permitted if the same does not increase the degree of nonconforming
bulk in such building.