In any district in which single-family dwellings are permitted, notwithstanding limitations imposed by other provisions of this chapter, a single-family dwelling and customary accessory buildings may be erected on any single lot of record at the effective date of adoption or amendment of this chapter. 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 areas 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. Yard requirement variances may be obtained through approval of the planning commission.

Where, at the effective date of adoption or amendment of this chapter, lawful use of land exists that is made no longer permissible under the terms of this title as enacted or amended such use may be continued, so long as it remains otherwise lawful, subject to the following provisions:

Where a lawful structure exists at the effective date of adoption or amendment of this chapter that could not be built under the terms of this title by reason of restrictions on area lot coverage, height, yards or other characteristics of the structure or location on the lot, such structure may be continued so long as it remains otherwise lawful, subject to the following provisions:

If a lawful use of a structure or of a structure and land in combination exists at the effective date of adoption or amendment of the ordinance codified in this title, that would not be allowed in the district under the terms of this title, the lawful use may be continued so long as it remains otherwise lawful, subject to the following provisions:

On any building devoted in whole or in part to any nonconforming use, work may be done in any period of twelve consecutive months on ordinary repairs or on repair or replacement of nonbearing walls, fixtures, wiring or plumbing to an extent not exceeding fifty percent of the assessed value of the building; provided, that the cubic content of the building as it existed at the time of adoption of the ordinance codified in this title shall not be increased. Nothing in this title 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.

There may be a change of tenancy, ownership or management of any existing, nonconforming uses of land, structures and premises; provided, there is no change in the nature or character of such nonconforming uses.