§ 200-179. R-4 Residence District use and bulk regulations.

A. 

Permitted uses. In an R-4 District, no building or premises shall be used and no building shall be erected or altered which is arranged, intended or designed to be used except for one or more of the following uses:

(1) 

Any permitted use in an R-2 District, subject to the bulk and area regulations of that district, as set forth in § 200-161 of this Part 4.

(2) 

With sewer and public water: patio house, single-family zero lot line detached dwellings, townhouse, garden apartment and mid-rise apartment dwellings.

B. 

Conditional uses. In an R-4 District, the following uses may be permitted as conditional uses:

(1) 

Any use permitted by condition in an R-2 District.

(2) 

A planned residential development containing a combination of residential dwellings as permitted under Subsection A(2) of this section, subject to the following conditions and standards and conforming to the requirements for planned developments stipulated in Article XXXI of this Part 4.

(a) 

Minimum development area: 25 acres in contiguous parcels served by public water and sewer systems. For purposes of this requirement, streets existing prior to the development of a planned residential development shall not be deemed to divide acreage nor be part of the acreage.

(b) 

Maximum permissible average gross density. Five dwelling units per acre shall be the basic average gross density permitted, unless increases under the incentive options in Subsection B(3) below are permitted by the Planning Board, up to but not to exceed eight dwelling units per acre.

(c) 

Incentive options for increased gross density. Maximum permissible average gross density of a planned development may be increased under the following options:

[1] 

Open space. For each 1% of increased common open space above 40% acceptable to the Planning Board, the maximum permitted basic average gross density may be increased by 2%, up to a maximum density increase of 10%.

[2] 

Least cost housing. For each dwelling unit of nonsubsidized least cost housing provided above the permitted basic average gross density and maintained as such thereafter, an additional conventional dwelling unit may be built, up to a maximum increase in the basic average gross density of 10%.

[3] 

Low- or moderate-income housing. For each unit of housing subsidized by a federal, state or private subsidy program which provides units for low- or moderate-income families or individuals, including senior citizens, and maintained as such thereafter, an additional conventional dwelling unit may be built, up to a maximum increase in the basic average gross density of 30%.

[4] 

Planned development. Where the Planning Board grants approval for a planned development, the maximum permitted average gross density may be increased as follows:

	Planned Development Acreage	Density Increase
	25 - 50	5%
	Over 50	10%

[5] 

Increases under Subsection B(2)(c)[1], [2], [3] and [4] above may be cumulative. However, the increases permitted shall not exceed the maximum permissible average gross density of eight dwelling units per acre.

(d) 

Minimum tract frontage: 100 feet in total as measured along a public street which provides access to the planned development.

(e) 

Residential unit type; distribution and net density. There shall be a variety of housing types and densities within a planned development and complying with the following:

[1] 

Residential unit distribution.

[a] 

At a minimum, two of the permitted housing types shall be provided.

[b] 

Of the housing types provided, no one type shall exceed 80% of the total dwelling units of a planned development, except that if mid-rise apartments are provided, they shall not exceed 40% of the total dwelling units.

[2] 

The net density of particular types of dwelling units shall be in accordance with the schedule below. In calculating permitted net densities as outlined herein, the area of land covered by such uses shall include internal streets, parking areas and all private yards, but not areas designated as common open space or development collector streets.

[a] 

The net density of single-family patio homes and zero lot line dwellings shall not exceed five dwelling units per acre.

[b] 

The net density of townhouses shall not exceed 10 dwelling units per acre.

[c] 

The net density of garden apartments shall not exceed 15 dwelling units per acre.

[d] 

The net density of mid-rise apartments shall not exceed 25 dwelling units per acre.

(f) 

Maximum improvement coverage: 35%, except 40% if at least 10% of the total dwelling units in a planned residential development are single-family patio homes or zero lot line dwellings. If less than 10% single-family uses is provided, the maximum improvement coverage shall be adjusted proportionately.

(g) 

Bulk requirements.

[1] 

Building heights for all building types exclusive of mid-rise apartments may vary from one to four stories, but in no case shall they exceed 45 feet.

[2] 

Building heights for mid-rise apartments may vary from four to six stories, but in no case shall they exceed 70 feet.

[3] 

Lot sizes and dimensions, yard sizes and building arrangement may be freely disposed and arranged, provided that the planned development conforms to a development plan approved by the Planning Board pursuant to the applicable provisions contained in Part 1, Site Plan Review, Part 2, Subdivision, and Part 3, Subdivision and Site Plan Procedures, of this chapter. In review of such development plans, the Planning Board shall also be guided by the design principles contained in § 200-190A(2)(h)[2] of this article.

C. 

Common open space. The common open space conditions pertaining to a PRN-1 District as contained in § 200-190C of this article shall apply to a planned development in the R-4 District.