City of Charlotte RIO: Residential Infill Overlay District Requirements
The RIO Residential Infill Overlay District in the City of Charlotte establishes scaled development standards for infill projects, limiting sidewall heights to a 20-foot maximum (or the blockface average) and requiring a 45-degree building height plane. It restricts building size based on either the average heated square footage of existing homes on the blockface or a calculation of 800 square feet per dwelling unit. This overlay is applied to at least 15 contiguous acres within specific Neighborhood 1 (N1) zoning districts to ensure new construction maintains the established neighborhood pattern.
Purpose and Applicability
The RIO Residential Infill Overlay District is intended to facilitate residential infill development within the City of Charlotte’s Neighborhood 1 Zoning Districts. The primary goal of the RIO District is to complement existing neighborhood patterns and scales by implementing specific controls on building height and dwelling unit size [Section 14.5.A].
The City of Charlotte applies the RIO District under the following conditions:
- Underlying Zoning: It may only be applied as an overlay to the N1-A, N1-B, N1-C, N1-D, and N1-E Zoning Districts [Section 14.5.B.2.a].
- Minimum Area: The RIO District must consist of at least 15 contiguous acres. This acreage calculation excludes properties developed with nonresidential uses or residential uses other than single-family, duplex, or triplex dwellings [Section 14.5.B.2.b].
- Boundary Rules: If a lot is included in a City of Charlotte RIO District, all lots on that same block must be included, encompassing all blockfaces [Section 14.5.B.2.b].
- Exclusions: The RIO District cannot be applied in combination with the HDO (Historic District Overlay), HDO-S (Streetside Historic District Overlay), or NCO (Neighborhood Character Overlay) [Section 14.5.B.2.c].
Permitted Uses
Once established by the City of Charlotte, the standards of the RIO District apply to single-family, duplex, and triplex dwellings. These standards replace the corresponding standards of the underlying zoning district. The RIO District standards do not apply to nonresidential development [Section 14.5.B.3]. All uses permitted in the underlying zoning district are allowed, and the RIO District may not prohibit any use allowed by the base district [Section 14.5.C.2].
Dimensional and Design Standards
The City of Charlotte mandates specific architectural and siting requirements for the RIO Residential Infill Overlay District to manage the massing of new construction.
Siting and Height Standards
| Standard | RIO Residential Infill Overlay Requirement |
|---|---|
| Front Setback from Street | Must be the average of the two closest residential buildings on the same blockface (minimum 10 feet). A survey is required at the time of permitting [Section 14.5.C.1.a]. |
| Maximum Sidewall Height | Limited to 20 feet. If the average height of facing sidewalls on both sides of the lot exceeds 20 feet, the height may be increased to that average [Section 14.5.C.1.b]. |
| Building Height Plane | A 45-degree plane starting at the maximum permitted sidewall height at the minimum side setback. The building may not exceed the underlying district's maximum height [Section 14.5.C.1.c]. |
| Sidewall Calculation Point | Measured from the finished floor elevation of the ground floor to the eave (or bottom of the roof plane if no eave exists) [Section 14.5.C.1.b.i]. |
Building Size and Massing
The City of Charlotte limits the total heated square footage of principal residential buildings within the RIO District based on existing neighborhood context.
| Standard | RIO District Calculation Method |
|---|---|
| Maximum Building Size | The greater of: (A) The average single-family dwelling size on the subject blockface, or (B) The number of residential units multiplied by 800 square feet per unit [Section 14.5.C.1.d.ii]. |
| Single-Family Allowance | Single-family dwellings are permitted to exceed the calculated maximum size by an additional 25% [Section 14.5.C.1.d.iii]. |
The 45-Degree Height Plane
The City of Charlotte utilizes a 45-degree height plane to transition building mass away from side lot lines. For every one foot of horizontal distance the building is moved inward from the required minimum side setback, one additional foot of height is allowed, starting from the maximum permitted sidewall height [Section 14.5.C.1.c.i].
- Dormers and Gables: These elements may extend through the 45-degree height plane, but their cumulative width is limited to 25% of the depth of the sidewall [Section 14.5.C.1.c.ii].
Administrative and Approval Process
Initiation of a RIO District in the City of Charlotte may be through a majority vote of the City Council or by a petition signed by 51% of property owners within the proposed geographic area [Section 14.5.B.1]. The formal application for the RIO District requires an amendment to the Official Zoning Map of the City of Charlotte, following the procedures in Section 37.2 [Section 14.5.D].
Sections Cited
- Section 14.5 RIO Residential Infill Overlay
- Section 14.2 HDO Historic District Overlay
- Section 14.3 HDO-S Streetside Historic District Overlay
- Section 15.4 Principal Uses: Prescribed Conditions
- Section 37.2 Zoning Map Amendments