In Tantlinger v. Zoning Hearing Bd. of South Union Township, 103 Pa. Commw. 73, 519 A.2d 1071 (Pa. Cmwlth. 1987), the ordinance permitted, in the R-1 district, two single-family residences on a lot with a minimum area of 22,500 square feet. Prior to the enactment of the ordinance, the owner established two dwellings on a lot of less than 15,000 square feet, one a mobile home, a use not allowed in R-1, and the other a conventional house. The property owner sought, and the zoning hearing board (ZHB) denied, permission to replace the nonconforming mobile home with a modular home, which the ordinance permitted in R-1. Common pleas affirmed, as did the court. The Court stated that the complete removal of a nonconforming use and replacement with a conforming use constitutes an abandonment of the nonconformity and, inasmuch as the lot's size could not legally accommodate both residences, the addition of the modular home would violate the ordinance.