Within the districts established by this chapter, or amendments that later may be adopted, there exist lots, structures and uses of lots and structures which were lawful before this chapter was enacted or amended but which would be prohibited, regulated, or restricted under the terms of this chapter or future amendment. It is the intent of this chapter to permit these nonconformities to continue until they are removed but not to encourage their survival. It is further the intent of this chapter that nonconformities shall not be enlarged upon, extended or expanded nor be used as grounds for adding other structures or uses prohibited elsewhere in the same district.

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 carried out diligently. "Actual construction" is hereby defined to include the placing of construction materials in permanent position and fastened in a permanent manner. Where excavation or demolition or removal of an existing building has been substantially begun preparatory to rebuilding, such excavation or demolition or removal shall be deemed to be actual construction, provided that work shall be carried on diligently.

Such lot must be in separate ownership and not of continuous frontage with other lots in the same ownership. This provision shall apply even though such lot fails to meet the requirements for area or width, or both, that are generally applicable in the district, provided that yard dimensions and other requirements not involving area or width, or both, of the lot shall conform to the regulations for the district in which such lot is located.

If two or more lots or combinations of lots and portions of lots with continuous frontage in single ownership are of record at the time of the adoption or amendment of this chapter, and if all or part of the lots does not meet the requirements established for lot width or area, the lands involved shall be considered to be an undivided parcel for zoning purposes, and no portion of said parcel shall be used or sold in any manner which diminishes compliance with the lot width and area requirements of this chapter, nor shall any division of any parcel be made which creates a lot with width or area below the requirements stated in this chapter.

No such nonconforming use shall be enlarged or increased, nor extended to occupy a greater area of land than was occupied by such use on the effective date of adoption or amendment of this chapter.

No such nonconforming use shall be moved in whole or in part to any portion of the lot or parcel other than that occupied by such use on the effective date of the adoption or amendment of this chapter.

If any such nonconforming use of land ceases for 12 months or more, any subsequent use of such land shall conform to the regulations specified by this chapter for the district in which the land is located.

This section shall not be deemed to apply to residential lots described in § 165-7B.

No such nonconforming structure may be enlarged or altered in any way which increases its nonconformity, but any structure or portion thereof may be altered to decrease its nonconformity.

Should such nonconforming structure or nonconforming portion of the structure be abandoned for 12 months or more or damaged or destroyed by fire or other cause or its use diminished by eminent domain taking to the extent of more than 50% of its replacement cost at the time of the damage or destruction or taking, and a building permit for such reconstruction, repair or replacement is not applied for within six months after such event, such structure may not be reconstructed except in conformity with the provisions of this chapter.

Should such structure be moved, for any reason, for any distance whatever, it shall thereafter conform to the regulations for the district in which it is located after it is moved.

This section shall not be deemed to apply to residential lots described in § 165-7B.

No existing structure devoted to a use not permitted by this chapter in the district in which it is located shall be enlarged, extended, constructed, reconstructed, moved, or structurally altered except in changing the use of the structure to a use permitted in the district in which it is located.

Any nonconforming use may be extended throughout any parts of a building which were manifestly arranged or designed for such use at the time of the adoption or amendment of this chapter, but no such use shall be extended to occupy any land outside such building.

If no structural alterations are made, any nonconforming use of a structure and premises may, as a special exception, be changed to another nonconforming use provided that the Zoning Board of Adjustment shall find that the proposed use is equally appropriate or more appropriate to the district than the existing nonconforming use. In permitting such change, the Zoning Board of Adjustment may require appropriate conditions and safeguards in accord with the provisions of this chapter.

Any structure, or structure and land in combination, in or on which a nonconforming use is superseded by a permitted use shall thereafter conform to the regulations of the district, and the nonconforming use may not hereafter be resumed.

When a nonconforming use of a structure, or structure and premises in combination, is discontinued or abandoned for 12 consecutive months or more (except where government action impedes access to the premises), the structure, or structure and premises in combination, shall not thereafter be used except in conformity with the regulations of the district in which it is located.

Where nonconforming use status applies to a structure and premises in combination, voluntary removal or destruction of the structure shall eliminate the nonconforming use status of the land. Destruction for the purpose of this subsection is defined as damage to an extent of more than 50% of the replacement cost at the time of removal or destruction.

Should such nonconforming use of a structure or nonconforming portion of a structure covered by this section be damaged or destroyed by fire or other cause, or its use diminished by eminent domain taking to the extent of more than 50% of its replacement cost at the time of the damage, destruction or taking, and a building permit for such reconstruction, repair or replacement is not applied for within six months after such event, such structure may not be reconstructed except in conformity with the provisions of this chapter.

This section shall not be deemed to apply to residential lots described in § 165-7B.

On any nonconforming structure or portion of a structure containing a nonconforming use, work may be done on ordinary repairs, or on repair or replacement of nonbearing walls, fixtures, wiring, or plumbing, to an extent not exceeding 10% of the current replacement cost of the nonconforming structure or nonconforming portion of the structure, as the case may be, provided that the cubic content existing when it became nonconforming shall not be increased.

If a nonconforming structure or portion of a structure containing a nonconforming use becomes physically unsafe or unlawful due to a lack of repairs and maintenance and is declared by any duly authorized official to be unsafe or unlawful by reason of physical condition and such condition continues without the institution of corrective action for 30 days after notice thereof from said official, it shall not thereafter be restored, repaired, or rebuilt except in conformity with the regulations of the district in which it is located.

Nothing in this chapter shall be deemed to prevent the strengthening or restoring to a safe condition of any building or part thereof declared to be unsafe by any official charged with protecting the public safety, upon order of such official.