A building may be erected or altered on any lot held at the effective date of this chapter in single and separate ownership which is not of the required minimum area, or width, or is of such unusual dimensions that the owner would have difficulty in providing the required minimum setbacks for the district in which such lot is situated, provided a special exception is authorized by the Zoning Hearing Board, and provided further that the applicant does not own or control other adjoining property that, when combined, would be sufficient to enable them to comply with the provisions of this chapter, as amended. In considering a special exception to permit erection or alteration of a building on a lot nonconforming as to area and bulk requirements, the Zoning Hearing Board shall impose the following additional requirements:
(1) That the use of the lot shall be required to conform to the permitted uses in the district in which such lot lies.
(2) That the building height shall be restricted to that specified for other buildings within the district in which the lot lies.
(3) That the design standards imposed for uses within the district in which the lot lies may be applied to the use of the lot.
(4) Impose such conditions as are necessary to assure compliance with the general purpose and intent of the Zoning Ordinance.