There shall be provided and maintained in accordance with those regulations, off-street automobile parking and loading spaces for every building and use. No building or structure shall be erected or use established and no existing building shall be structurally altered, unless there be already in existence, or unless provision therefore is made concurrently with such erection or structural alteration or new use, the number of parking spaces and loading spaces necessary to meet the minimum requirements hereinafter set forth. (Prior gen. code § 8-63.0)