Lawful uses of land or buildings may be continued if they were existing or under construction at the time the ordinance codified in this title was adopted, even if such uses do not conform with the provisions of the zone in which they are located. The intent of these regulations is to permit continuance of such uses until they are removed, but not to encourage their perpetuation or expansion. Nonconforming uses are declared by this title to be incompatible with the uses permitted in the district involved. It is the further intent of this title that nonconformities shall not be used as grounds for adding other structures or uses prohibited elsewhere in the same district.

To avoid undue hardship, nothing in this title shall be deemed to require a change in plans, construction or designated use of any building for which a building permit has been issued prior to the effective date of adoption or amendment of the ordinance codified in this title and upon which actual building construction has been started prior to the expiration date of the permit. "Actual construction" is hereby defined to include the placing of construction materials in permanent positions and fastened in a permanent manner, and demolition, elimination and removal of an existing structure in connection with such construction; provided, that actual construction work shall be diligently carried on until completion of the building involved.

The existing use of a structure, if it was lawful at the effective date of this code, may continue although such use does not conform to the regulations contained herein; provided, that if such nonconforming use is abandoned, any future use of the structure shall conform to the regulations of the district in which it is located.

Discontinuance of a nonconforming use of land, structure or building for a continuous period of one year shall be prima facie evidence of intention to abandon.

A nonconforming use may be continued by successive owners or tenants, except where that use has been abandoned. No changes to different uses shall be made unless that change conforms to the regulations of this code.

A person may not make or cause to be made any expansions to a nonconforming site unless that change conforms to the regulations of this code.

Ordinary maintenance and repair of a nonconforming building and its equipment or fixtures is permitted, provided the value of the repair does not exceed twenty-five percent of the assessed value of the building as determined by the borough assessor for the year in which the work is done.

The provisions of this chapter relative to additions and enlargements, restoration of damaged buildings, and abandonment shall not apply to any residential use; provided, however, this clause shall not be so interpreted to permit an increase in the number of dwelling units or bedrooms within any such residential building.

The foregoing provisions of this chapter shall also apply to any nonconforming use in any zone district hereafter changed to a more restrictive use district or to a zone district hereafter established for areas not previously covered by the official zoning maps.