A.
Within the zones established by this chapter or amendments that may later be adopted, there exist lots, structures, and uses of land and structures that were lawful before this chapter was adopted or amended but which would be prohibited, regulated, or restricted under the terms of this chapter, or future amendments.
B.
This chapter intends to permit these nonconformities to continue until they are removed but not to encourage their survival. This chapter declares such uses to be incompatible with permitted uses in the zones involved. It is further the intent of this chapter that nonconformities shall not be enlarged upon, expanded, or extended, nor be used as grounds for adding other structures or uses prohibited elsewhere in the same zone.
C.
A nonconforming use of a structure, a nonconforming use of land, or a nonconforming use of a structure and land shall not be extended or enlarged by attachment on a building or premises of additional signs intended to be seen from off the premises or by the addition of other uses of a nature which would be prohibited in the zone involved.
D.
To avoid undue hardship, nothing in this chapter shall be deemed to require a change in the plans, construction, or designated use of any building on which actual construction was lawfully begun prior to the effective date of adoption or amendment of this chapter, and upon which actual building construction has been diligently carried on. Actual construction is now defined as the placing of materials in a permanent position and fastened permanently, except that where demolition or removal of an existing building has been substantially begun preparatory to rebuilding, such demolition or removal shall be deemed to be actual construction, provided that work shall be diligently carried on until completion of the building involved.