Where a violation of this chapter is determined to exist, the Building Inspector shall serve notice either by certified mail or personally on the owner, agent or contractor of a building, structure, or lot where such violation has been committed or shall exist, and, where practical, on the lessee or tenant of a part of or of an entire building, structure, or lot where such violation has been committed or shall exist; and, where practical, on the agent, architect, contractor or any other such person who takes part or assists in such violation, or who maintains any building, structure, or lot in which any such violation shall exist.