27.21.070 Two-Unit Development Standards
SB 9 units, as defined in this Chapter, shall comply with the following development standards:
(a) Demolition Limits. SB 9 projects that do not involve an urban lot split are subject to the following:
(1) Demolition of less than 50% of a structure's exterior structural walls or roof shall be subject to a ministerial review process.
(2) Demolition of 50% or more of a structure's exterior structural walls or roof may be permitted subject the Alternative Discretionary Review process listed in Section 27.21.045 of this Chapter and issuance of a Special Use Permit for the substantial removal of the existing structure pursuant to Section 27.18.035 of the San Mateo Municipal Code.
(b) Maximum Floor Area Ratio. The maximum Floor Area Ratio (FAR) for all structures on site shall be determined by the underlying zoning district with the following exceptions:
(1) Application of development standards of the underlying zoning district shall not preclude the construction of up to two primary dwelling units nor physically preclude either of the two units from being at least 800 square feet in floor area.
(2) SB 9 unit(s) in excess of 800 square feet shall be subject to a Single-Family Dwelling Design Review (SFDDR) or Site Plan and Architectural Review (SPAR) discretionary review process and shall be governed by the maximum floor area established by the underlying zoning district.
(3) In instances where the existing floor area allowance of a lot has been fully utilized, an SB 9 unit of up to 800 square feet in size with at least 4-foot side and rear yard setbacks and up to 16-feet in height shall be permitted, unless the proposed development would have a specific adverse impact, as defined and determined in paragraph (2) of subdivision (d) of Section 65589.5, as amended, of the Government Code, upon public health and safety or the physical environment, and for which there is no feasible method to satisfactorily mitigate or avoid the specific adverse impact(s).
(c) Height. The specific height maximums outlined below are applicable to all zoning districts subject to the Two-Unit Development Overlay District:
(1) Attached SB 9 Units. The maximum building height is 24 feet to top of plateline and 32 feet to roof peak as measured from existing grade.
(2) Detached SB 9 Units. Maximum building height is 16 feet to top of plateline and 24 feet to roof peak as measured from existing grade.
(d) Setbacks. SB 9 unit(s) shall have setbacks as follows:
(1) Front Setback. A minimum setback from the front lot line, as required by the lot's underlying zoning district.
(2) Side and Rear Setbacks. A minimum setback of four (4) feet shall be required from the side and rear lot lines.
(3) No setback shall be required for an existing legally permitted structure that is converted into an SB 9 unit or a structure constructed in the same location and to the same dimensions as an existing legally permitted structure.
(1) General Requirements. There shall be a minimum of one standard size off-street parking space (either uncovered or covered) for each SB 9 unit. All parking, whether required or voluntary, shall be located entirely on the same lot as the dwelling unit it serves and shall conform to the size requirements of the City's "Standard Drawings and Specifications" as adopted by resolution of the City Council and on file with the Department of Public Works. Covered parking shall meet all applicable setbacks of the underlying zoning district.
(2) Exemptions. No off-street parking shall be required for an SB 9 unit in the following instances:
(A) The parcel is located within one-half mile walking distance of a high-quality transit corridor, as defined in Public Resources Code Section 2155(b); as amended; or
(B) The parcel is located within one-half mile walking distance of a major transit stop, as defined in Public Resources Code Section 21064.3(e), as amended; or,
(C) The parcel is located within one block of a car share facility.
(f) Objective Design Standards.
(1) New residential construction of primary units subject to streamlined ministerial approval shall comply with the Interim Objective Design Standards as adopted by City Council resolution and as may be amended from time to time by further City Council resolution.
(g) Other Development Standards.
(1) All development pursuant to this Chapter shall also be subject to the requirements of the California Building Code, Fire Code and local fire sprinkler ordinance requirements.
(2) All objective standards of the underlying zoning district, Titles 27 and 23 and other relevant Titles of the San Mateo Municipal Code shall apply. If such standards conflict with this Chapter, the standards in this Chapter shall prevail. In no instance shall any objective building or design standard preclude the development of at least two primary dwelling units of at least 800 square feet each in size, unless the development would have a specific adverse impact, as defined and determined in paragraph (2) of subdivision (d) of Section 65589.5, as amended, of the Government Code, upon public health and safety or the physical environment, and for which there is no feasible method to satisfactorily mitigate or avoid the specific adverse impact(s).