If, within the zoning districts established by this chapter or due to amendments that may later be adopted, there exist lots, structures or uses of lots which were lawful before this chapter was passed or amended but which would be prohibited, regulated or restricted under the terms of this chapter or future amendments, it is the intent of this chapter to permit those nonconformities. Such uses are declared by this chapter to be incompatible with authorized uses in the zoning districts 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 signs, structures or uses prohibited elsewhere in the same zoning 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 structure on which actual construction was lawfully begun prior to the effective date of adoption or amendment of this chapter and upon which actual construction has been diligently commenced. "Actual construction" is hereby defined to include the placing of construction materials in permanent position and fastened in a permanent manner, except that where demolition or removal of an existing structure has 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 structure involved.

Where two or more adjacent lots of record with continuous frontage have less than the required area and width and are held by one owner, the lots shall be considered to be an undivided lot for the purpose of complying with this article. No division of any lot shall be made which does not comply with the requirements of this article.

Any lot of record existing at the effective date of this chapter and held in separate ownership different from the ownership of adjoining lots may be developed in accordance with the requirements of the zoning district of the lot of record.

Where structures exist on adjacent nonconforming lots of record which have front yards less than the minimum depth required, the minimum front yard for an adjacent undeveloped nonconforming lot of record shall be the average depth of the nonconforming front yards of the adjacent developed nonconforming lots which are in the same block on the same side of the street and in the same recorded plan as the undeveloped lot. Private garages, storage sheds, swimming pools and similar structures shall be located to the rear of the permitted principal structure and may be permitted in the rear yard, provided that they are no closer than 10 feet from the rear property line and are not located on any easements or rights-of-way.

No such nonconforming use shall be enlarged or increased or extended to occupy a greater lot area than was occupied at the effective date of adoption or amendment of this chapter, unless the Board shall interpret that the enlargement or extension is necessary by the natural expansion and growth of trade of the nonconforming use.

No such nonconforming use shall be moved in whole or in part to any other portion of the lot not occupied by such use at the effective date of adoption or amendment of this chapter.

If any such nonconforming use of a lot ceases for any reason for a period of more than 12 consecutive months, it shall be presumed that the nonconforming use has been abandoned, and any subsequent use of such lot shall conform to the regulations specified by this chapter for the zoning district in which such lot is located.

No such structure may be enlarged or otherwise have any structural alterations made to it in a way which increases its nonconformity, except when the Board may determine undue hardship and may authorize a reasonable modification of such structure.

Should such structure be destroyed by any means, repairs or reconstruction may be undertaken, provided that such restoration is started within 12 months of the date of damage.

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

No existing structure devoted to a use not permitted by this chapter in the zoning district in which it is located shall be enlarged, extended, constructed, reconstructed, moved or otherwise have any structural alterations made to it except in changing the use of the structure to an authorized use in the zoning district in which it is located, unless the Board shall interpret that the enlargement, extension, construction, reconstruction or structural alteration is necessitated by the natural expansion and growth of trade of the nonconforming use.

Any nonconforming use may be extended throughout any part of a structure which was manifestly arranged or designed for such use at the time of adoption or amendment of this chapter, but no such use shall be extended to occupy any lot or portion of a lot outside such structure, except on a lot or portion of a lot owned at the time the use became nonconforming.

Any structure or structure and lot in combination in or on which a nonconforming use is superseded by an authorized use shall thereafter conform to the regulations for the zoning district in which such structure is located, and the nonconforming use may not thereafter be resumed.

When a nonconforming use of a structure or structure and lot in combination ceases for a period of more than 12 consecutive months, it shall be presumed that the nonconforming use has been abandoned, and any subsequent use of such structure or structure and lot in combination shall conform to the regulations specified by this chapter for the zoning district in which such lot is located.

Where nonconforming status applies to both the use and the structure on the lot, removal or destruction of the nonconforming structure shall eliminate the nonconforming use on the lot.

Nonconforming signs may be repaired or reconstructed, provided that no structural alterations are made which increase the sign area computed in accordance with § 375-46 of this chapter.

Nonconforming signs may not be enlarged, added to, or replaced by another nonconforming sign, use or structure, except that interchange of poster panels shall be permitted.