1. A building permit may be issued for interior work to repair, maintain or alter nonconforming structures and structures with nonconforming uses regardless of whether the work is located in the conforming or nonconforming portion of the structure.

2. A building permit may be issued for work proposed to repair, maintain or improve the exterior of nonconforming structures and structures with nonconforming uses, including the nonconforming portion of the structure; provided, there are no changes to exterior openings (e.g., doors or windows), decks, or roof height of the nonconforming portion of the structure, and the cost of construction does not exceed sixty (60) percent of the current replacement value of the structure, as determined by the City Chief Building Official using the most current ICC assessed valuation data with a regional modifier.

3. Except as provided for in Larkspur Municipal Code Section 18.68.035, an exception permit shall be required for work proposed to repair, maintain or improve the exterior of nonconforming structures and structures with nonconforming uses when changes to exterior openings (e.g., doors and windows), decks, or roof height of the nonconforming portion of the building are proposed, or when the cost of construction exceeds sixty (60) percent of the current replacement value of the structure, as determined by the City Chief Building Official using the most current ICC assessed valuation data with a regional modifier. An exception permit shall be processed in accordance with Larkspur Municipal Code Section 18.68.040.

4. Maintaining a Nonconforming Setback. Except as provided for in Larkspur Municipal Code Section 18.68.035, if a foundation and the exterior walls above it, which encroach into a required setback, are removed or replaced, such foundation and walls shall be reconstructed in compliance with the setback regulations in the district. Minimum standards to retain a nonconforming setback are as follows:

1. In the R-1 and T-R zones, nonconforming structures and structures with nonconforming uses that have been damaged or destroyed, due to any means other than voluntary demolition, may be repaired or reconstructed to the footprint, building envelope, floor area, and exterior door, window and deck placement of the original structure, including its nonconforming features, subject to the following conditions:

2. In zones other than the R-1 and T-R Zoning Districts, nonconforming duplexes, multiple-family, and commercial structures and structures with nonconforming uses that have been damaged, due to any means other than voluntary demolition, may be repaired or restored to the footprint, building envelope, floor area, and exterior door, window, and deck placement of the original structure, including its nonconforming features, only where the cost of restoration does not exceed sixty (60) percent of the current replacement cost for the original structure. Such restoration shall comply with the requirements of subsections (B)(1)(a) through (d) of this section. If the cost of restoration of the structure exceeds sixty (60) percent of the current replacement cost, as determined by the City Chief Building Official using the most current ICC assessed valuation data with a regional modifier, the structure shall not be restored unless made to conform to the regulations of the district in which it is entitled.

1. Nonconforming structures may be expanded with a building permit; provided, that no exacerbation of the existing nonconformity shall occur, and that the expansion meets all other zoning regulations. Accepting that otherwise permitted in this chapter, a variance application shall be required for any proposal to increase existing nonconforming aspects of a structure.

2. In the R-1 Zoning District, nonconforming second units in existence prior to September 3, 1983, shall not be enlarged in area or reconfigured without being brought into compliance with Larkspur Municipal Code Chapter 18.23, Accessory Dwelling Units.

1. In zones other than residential, nonconforming uses and structures with nonconforming uses, and structures on properties with nonconforming uses, shall not be relocated or enlarged so as to occupy a greater area of land or building than occupied at the time the use became nonconforming, unless a use permit is granted for such change. A nonconforming use shall not be expanded to displace a conforming use. To grant such a use permit, the Planning Commission shall find, in addition to the findings required by Larkspur Municipal Code Section 18.76.050, at least one of the following circumstances exist:

2. In the R-1 and T-R Zoning Districts, duplexes, multiple-family dwellings, and dwelling groups may be expanded by no more than a maximum of one hundred (100) square feet per dwelling unit. Such expansion must be attached directly to an existing dwelling (i.e., no new detached structures, and no expansion of accessory structures), and cannot be aggregated (i.e., expansion of two hundred (200) square feet on one dwelling where two (2) dwellings exist on a site). Such expansion shall also be subject to approval of an exception permit, provided the proposed expansion conforms to all other zoning regulations.

3. Except as provided in this section, no nonconforming use, including nonconforming densities in the residential districts, shall be enlarged or extended so as to occupy a greater area of land or building than occupied at the time it became a nonconforming use.