Following the effective date of adoption of this chapter, a permitted principal structure and accessory structure(s) may be erected upon any single nonconforming lot of record. Said lot must be in separate ownership and not of continuous frontage with other lots in the same ownership at the time of adoption 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 However, yard dimensions and requirements other than those applying to area or width, or both, of the lot shall conform to the regulations for the district in which such lot is located. Variance of any prescribed requirements shall be obtained only through action of the Zoning Hearing Board. If two or more contiguous nonconforming lots held under single ownership have been duly approved by the Township Supervisors and are on record in the office of the Recorder of Deeds of Lebanon County for no more than three years before the date of adoption of this chapter, such lots may be developed, as recorded, provided that yard dimensions and requirements other than those applying to area or width shall conform to the regulations for the district in which such lots are located.