Modifying and Expanding Nonconforming Structures in Grass Valley
In the City of Grass Valley, nonconforming structures—those that were legally built but no longer meet current height, setback, or parking standards—may be modified or expanded under specific conditions. Most enlargements for nonresidential or multifamily buildings require a Minor Use Permit, while single-family dwellings have more flexible allowances for interior changes and limited exterior additions that do not exceed 25% of the existing floor area [Section 17.90.030].
General Principles for Nonconforming Structures
A nonconforming structure in the City of Grass Valley is defined as a building that was legally constructed before the adoption of the current Development Code but does not comply with current standards like setbacks, height limits, or off-street parking [Section 17.90.020].
The City of Grass Valley permits the continued use of these structures, including transfers of ownership, provided they meet the requirements of the code. Maintenance and safety improvements are generally encouraged:
- Ordinary Maintenance and Repair: Owners may perform routine maintenance and repairs on any nonconforming structure [Section 17.90.030.B.3].
- Seismic Retrofitting: Modifications required to reinforce unreinforced masonry or comply with earthquake safety standards are permitted, provided the work does not change the building's footprint or height [Section 17.90.030.B.4].
Expansion and Modification Requirements
The City of Grass Valley regulates the expansion of nonconforming structures based on the building's primary use. Discretionary permits are typically required to ensure that changes do not negatively impact neighboring properties.
| Structure Type | Action | Permit/Requirement |
|---|---|---|
| Nonresidential or Multifamily | Enlargement, extension, or relocation | Minor Use Permit [Section 17.90.030.B.1.a] |
| Single-Family Dwelling | Interior modifications | No limitation [Section 17.90.030.B.1.b] |
| Single-Family Dwelling | Addition complying with all current setbacks | Community Development Director approval [Section 17.90.030.B.1.b(1)] |
| Single-Family Dwelling | Addition encroaching into existing nonconforming setback | Minor Use Permit; addition must be < 25% of total floor area [Section 17.90.030.B.1.b(2)] |
| Accessory Structure | Conversion to an Accessory Dwelling Unit (ADU) | Must not exceed one story and must meet ADU standards [Section 17.90.030.B.2] |
Nonresidential and Multifamily Structures
Any expansion, extension, or relocation of a nonresidential or multifamily nonconforming structure in the City of Grass Valley requires a Minor Use Permit. The review authority must determine that the proposed work is compatible with neighboring land uses and will not adversely impact surrounding properties [Section 17.90.030.B.1.a].
Single-Family Dwellings
Owners of nonconforming single-family dwellings may make interior modifications without limitation. Exterior additions that meet all current setback requirements can be approved by the Community Development Director. If an owner wishes to build an addition that follows the line of an existing nonconforming setback, they must obtain a Minor Use Permit. This type of encroaching addition is strictly limited to less than 25% of the existing structure's total floor area [Section 17.90.030.B.1.b].
Reconstruction After Damage or Destruction
The City of Grass Valley provides specific rules for nonconforming structures that are involuntarily damaged (e.g., by fire or natural disaster):
- Residential Exceptions: A nonconforming single-unit or multi-unit dwelling that is involuntarily damaged may be reconstructed with the same footprint, height, and number of units [Section 17.90.040.A].
- The 50% Rule: For other structures, if the cost of repair is 50% or less of the structure's value before the damage, it may be restored to its previous size and use. If the damage exceeds 50% of the value, a Minor Use Permit is required for reconstruction [Section 17.90.050.B].
Substantial Expansion and Renovation
In the City of Grass Valley, a "substantial expansion" is defined as adding 25% or more to the floor area of a residential structure, or performing renovations valued at 50% or more of the structure's value. Such projects require both a Minor Use Permit and a Development Review Permit. Within Traditional Community Development Zones, these projects must specifically maintain the neighborhood character and encourage mixed-use development [Section 17.90.040].
Restrictions on Specific Modifications
Certain modifications are prohibited for nonconforming structures in the City of Grass Valley:
- Condominium Conversions: Apartment buildings that are nonconforming due to parking, setbacks, height, or yard space are not eligible for conversion to condominiums [Section 17.44.080.F].
- Increased Nonconformity: No modification or expansion may be approved that increases the degree of nonconformity (e.g., further reducing a required setback or exceeding height limits more than the current structure) [Section 17.90.050.H].
Sections Cited
- Section 17.44.080 - Condominium conversions
- Section 17.90.010 - Purpose
- Section 17.90.020 - Definitions
- Section 17.90.030 - Restrictions on nonconforming uses and structures
- Section 17.90.040 - Residential exceptions
- Section 17.90.050 - Loss of nonconforming status