No general building contractor or plumbing, electrical heating and/or sheet metal, piping sewer building, air conditioning or refrigeration, cement or asphalt, masonry, excavator, lot clearing, trenching installation, dry wall installation, gutter installation, painting, tile setting and floor covering contractors and landscapers shall perform any work within the City without first obtaining a certificate of registration from the Building Department.
(1978 Code Sec. 801.07)