Second Story Additions in Concord
In Concord, second-story additions for single-family dwellings are subject to Design and Site Review if the addition meets specific size criteria or if the property is located on a sloped lot [Section 18.415.020]. Furthermore, any second-story addition must comply with established zoning district height limits, setback requirements, and the Concord Objective Design Standards to ensure compatibility with the surrounding neighborhood [Section 18.152.010, Section 18.30.030].
Design and Site Review Applicability
Design and Site Review is required for specific types of single-family dwelling additions to ensure they maintain the existing character of the neighborhood [Section 18.415.010]. Specifically, Design and Site Review is triggered for single-family residences in the following cases [Section 18.415.020]:
- Size of Addition: Any second-story addition where the area of the second-floor portion is 40 percent or more than the area of the original structure located on the second floor [Section 18.415.020].
- Setback Proximity: Any second-story addition that is set back less than 10 feet from a side property line [Section 18.415.020].
- Sloped Lots: Any addition to an existing single-family dwelling on a sloped lot, as defined by the Hillside Protection regulations in Chapter 18.300 [Section 18.415.020].
Development Standards for Residential Districts
All residential structures, including second-story additions, must adhere to the development standards of their respective zoning district, including maximum building height and setback requirements [Section 18.30.010].
RR and RS Districts
For Rural Residential (RR) and Residential Single-Family (RS) districts, the development standards are summarized in the table below:
| Standard | RR-20/RR-40/RR-15 | RS-6 | RS-7/RS-7.5 | RS-8 | RS-10/RS-12 |
|---|---|---|---|---|---|
| Max Building Height | 30 feet | 30 feet | 30 feet | 30 feet | 30 feet |
| Front Setback | 25/30/20 feet | 20 feet | 20 feet | 20 feet | 20 feet |
| Interior Side Setback | 10 feet | 5/10 feet | 5/10 feet | 5/10 feet | 10 feet |
| Rear Setback | 30/50/30 feet | 15 feet | 20 feet | 20 feet | 25 feet |
Note: For the RS-6 through RS-8 districts, interior side setbacks are listed as 5, 10 feet [Section 18.30.030].
RL, RM, and RH Districts
For Residential Low Density (RL), Medium Density (RM), and High Density (RH) districts, building height is regulated as follows:
| District | Maximum Building Height |
|---|---|
| RL | 30 feet |
| RM | 40 feet |
| RH | 67 feet |
Note: Additional height in RM and RH districts may be approved with a use permit [Section 18.30.040].
Objective Design Standards
Residential projects, including significant additions, must comply with the 2023 City of Concord Objective Design Standards [Section 18.152.030]. If a project does not conform to these objective standards, it is subject to the full Design and Site Review process [Section 18.152.050]. Key considerations for second-story additions under these standards include:
- Privacy: Design should avoid direct lines of sight to existing neighboring units through the staggering of window and door placement [Section 18.152.050].
- Building Mass: Second stories should be recessed relative to the first story to reduce the appearance of building mass and preserve the privacy of adjacent properties [Section 18.155.060].
Procedures
- Application: Property owners must file an application for Design and Site Review with the planning division [Section 18.415.050].
- Approval Authority: The planning division serves as the initial review authority for Design and Site Review and may refer the application to the design review board or planning commission [Section 18.415.040].
- Findings: The review authority will approve the addition upon finding that it is compatible with the site, consistent with the character of the neighborhood, and protects the natural environment [Section 18.415.100].
Sections Cited
- Section 18.30.010 (Purpose)
- Section 18.30.030 (Table 18.30.030 – RR and RS districts – Development standards)
- Section 18.30.040 (Table 18.30.040 – RL, RM, and RH districts – Development standards)
- Section 18.150.010 (Purpose)
- Section 18.152.010 (Purpose and intent)
- Section 18.152.030 (Relationship to other standards and requirements)
- Section 18.152.050 (Review and decision procedure)
- Section 18.155.060 (Design criteria for small lot single-family subdivisions)
- Section 18.300.010 (Purpose)
- Section 18.415.010 (Purpose)
- Section 18.415.020 (Applicability)
- Section 18.415.040 (Discretionary review authority)
- Section 18.415.050 (Application)
- Section 18.415.100 (Discretionary decision and findings)