Conserve open space areas and amenities within developments, and, in the case of subdivisions of significant size, provide open space areas for passive and/or active recreation use.

Promote the more efficient use of land to permit its maximum use while preserving aesthetics and natural resources.

Accommodate housing and other development which is more affordable by consolidating improvements, utilities, and land alteration.

As an option permitted in the PD-1 and R-1 Districts of this chapter, a developer may be allowed to modify the area and bulk regulations where the tract of land has a minimum gross area of 12 1/2 acres and is used exclusively for open space in accordance with § 27-1317.

The tract to utilize such option shall be in single and separate ownership, or, in the case of multiple ownership, the tract shall be developed according to a single plan with common authority and responsibility.

The maximum gross density of any development utilizing the cluster development option shall be based on an actual site yield plan and not on gross land area when determining density of use and shall not exceed that allowed by the applicable zoning district.

Site planning, including the layout of streets and lots and placement of structures and the layout of open space shall be, in the judgment of the Borough Council, in compliance with the purposes of this section.

A minimum of 12 1/2 acres and no less than 25% of the total area in a cluster development shall be designed as and used exclusively for open space. The ownership, location, design, layout, and maintenance of open space within such development shall be in accordance with § 27-1317.

The yard reduction option may be used for any building or structure in any district as provided in this section, except the C-3 District.

Where a reduced yard area is proposed under this section, the abutting property(s) along the lot lines where reduced yard is proposed must be held under the same ownership at the time of application for development or the owners of abutting properties must record an agreement or deed restriction and consent in writing to such reduced yard and other easements and restrictions specified in this section.

A dwelling may be placed within one side lot yard or a side and rear lot yard to a zero-foot setback, but shall share not more than one common party wall with another building.

No more than two lot lines may have reduced yards for any single lot.

Where a side yard is reduced, the opposite side yard on the lot and the side yard on the adjacent lot abutting the reduced yard shall be at least twice as great as the minimum side yard normally required by the applicable zoning district.

To avoid narrow, confined, and unusable yard space, the wall of a dwelling along a reduced rear yard shall not oppositely face nor be generally parallel to the rear wall of a dwelling on an abutting lot if a common party wall is not created or if such adjacent rear dwelling wall is within 20 feet of the property line. See Figure two for illustration of this requirement.

For commercial, industrial, or office buildings, a zero-foot yard may be permitted along side and/or rear lot lines of abutting lots to create a common party wall(s) between buildings along no more than two lot lines.

A zero-foot side or rear yard, possibly creating a common party wall, may be permitted for garages; utility or storage sheds; fences, walls or trellises over eight feet in height; or other uninhabitable accessory structures which are designed to abut each other.

Building roofs shall be designed so that water runoff is confined to the lot on which the roof is located and is not directed into any reduced yard permitted under this section.

The easements, deed restrictions, and agreements necessary to comply with this paragraph shall be irrevocable covenants that run with the land as long as the reduced yard condition exists. Such easements and restrictions shall be recorded with the Recorder of Deeds office of Chester County. Proof of such recorded easements and restrictions shall be submitted to the Borough prior to issuance of a building permit.

All lots shall be deed restricted to prohibit doors, windows, air-conditioning units, or any other type of openings, or projections in a dwelling wall facing and generally parallel to the reduced side or rear yard.

Walls and fences within the reduced yard that face or are generally parallel to an abutting lot shall be maintained in their original color and treatment unless otherwise agreed to in writing by the two affected lot owners.

Where a yard is reduced to between zero feet and five feet of a lot line, a joint- use easement shall be established between the lot owner and the adjacent lot owner for the land located within the reduced side or rear yard for the length of a building wall, fence or other structure. It shall be the responsibility and obligation of the adjacent property owner to maintain the reduced yard within the easement, and such owner will have use of the easement area for enjoyment. No shrubbery, trees or structures shall be placed in the reduced yard which would interfere with the property owner's maintaining his building. The adjacent lot owner who has the use of the easement shall be responsible for all damages to the adjacent dwelling that result from direct or indirect use and enjoyment of his side yard.

Where a yard is reduced to zero feet and a common party wall is not created, a joint-use easement shall be established between abutting landowners. The easement shall be a minimum five-foot-wide strip of land within the adjacent lot abutting the reduced yard. The easement shall be parallel to and abutting the lot line for five feet beyond the end of the structure that sits on the lot line. It shall be the responsibility and obligation of the adjacent property owner to maintain the easement on his lot, and such owner will have use of the easement area for enjoyment, except that no shrubbery, trees, or structures shall be placed in the easement which would interfere with the adjacent property owner's maintaining his building. The landowner who owns the easement land shall be responsible for all damages to the structure that sits on the lot line that result from direct and indirect use and enjoyment of his yard. The adjacent lot owner shall have use of the easement to maintain his building, but he shall be responsible for any damages to the easement owner's yard that result while maintaining his building.

A tract size of at least five acres is required.

The tract of land to be developed shall be in one ownership, or in the case of multiple ownership, it shall be developed according to a single plan with common authority and responsibility.

The development shall be served by public sewage facilities and public water supply.

Permitted uses include single-family detached, single-family semidetached, two-family and multiple-family dwellings, and mobile homes on individual lots.

Convenience commercial facilities to serve the residents of the mixed residential community may be provided if the development contains a minimum of 100 dwelling units. All convenience commercial facilities shall comply with the following standards:

Nonprofit recreational uses may be incorporated into the development and its common open space.

The maximum allowable gross residential density shall be three dwelling units per gross acre on the entire tract.

The maximum allowable net density for any dwelling type shall be six dwelling units per acre within the tract.

Each mixed residential community shall consist of at least two of the following dwelling unit types:

The percentage and mix of the housing stock type shall be left to the discretion of the developer, except that the minimum percentage of any dwelling unit type shall be 20% and single-family detached dwellings will comprise no more than 50% of all dwelling units.

The requirements of § 27-1212 shall apply to multiple-family dwellings.