Exception to area requirements. A single-family dwelling may be constructed in a district where permitted on any lot shown on a recorded subdivision plat or any lot of official record at the time of enactment of this chapter, the owner of which does not own any adjoining lot or adjacent land, provided that in the opinion of the Board of Adjustment the lot and proposed yard spaces satisfy as closely as possible the lot and yard requirements of this chapter for the district in which such lot is located. Where the owner of a substandard-size lot owns adjacent lots or parcels of land, such lots or parcels shall be considered as a single lot, and the area and yard space provisions of the chapter shall hold.