Purpose and General Requirements for All Uses in R-4 Zone. The R-4 Residential/Professional Zone is a zone for a single family residential use, and a zone which permits the conversion of existing residential homes, constructed prior to October 1, 1993, fronting on Main Street and Glen Road and the proposed service road parallel to Main Street as shown in the Town Center Master Plan Amendment. Professional office and service uses are permitted as a conditional use. Site plans and building shall be designed in a manner that will preserve the rural and historic character of the Township, preserve the tax base of the Township and promote the viability of the existing and future commercial areas in the central business district, promote the public health, safety, morals and general welfare, provide adequate open space and preservation of environmentally sensitive lands such as freshwater wetlands, transition areas, severe slopes and woodlands, promote development in harmony with the existing Town Center by maintaining the scale, form and proportions of the existing R-4 and the Town Center Zones. The R-4 Residential/Professional Zone therefore promotes the establishment of appropriate single family/residential, planned residential unit developments and office and service uses at locations in accordance with their respective environmental requirements, and the promotion of desirable visual environment through creative development techniques including unified design, conservation of open space and prevention of urban sprawl. Demolition or partial demolition of any structures in the R-4 Zone shall comply with Subsection 18-4.2 regarding Historic Preservation.