Pursuant to Code of Virginia, § 15.2-2307, any lot, use, structure, or sign which subsequently becomes nonconforming as a result of adoption or amendments to this chapter may continue as it was at the time of the adoption or amendment, as long as it remains otherwise lawful. Such nonconforming lots, uses, structures, and signs shall conform to all laws in effect at the time when the use, structure, or sign was established.