Redwood City, CA Building Safety: Anti-Mansionization (2026)
Key Facts
- Review trigger
- gross floor area over 3,000 sq ft AND FAR over 45%
- Review body
- Planning Commission, public hearing
- Exempt
- ground floor additions; lots under 5,000 sq ft
- Also exempt
- 2nd-story additions of 100 sq ft or less
- ADUs
- excluded from Article 48 entirely
- Adopted
- Ord. No. 1130-379, 8-26-19
Summary
Redwood City's floor-area-ratio ordinance forces a public Planning Commission hearing for any single-family home whose gross floor area tops 3,000 square feet and whose floor area ratio exceeds 45 percent, the city's main check on outsized "mansionization" additions and new builds.
48.2 - Applicability. This Article shall apply to all Architectural Permit applications for single-family dwellings in any zoning district except as described below. This Article shall not apply to any accessory dwelling units described in Article 37, or the following: A.Ground floor additions; orB.New single-family dwellings or additions built on a lot that is less than five thousand (5,000) square feet; orC.Second story additions of one hundred (100) square feet or less. 48.4 - Planning Commission Review and Additional Findings. Architectural Permit applications for single-family dwellings with a gross floor area exceeding three thousand (3,000) square feet and a floor area ratio exceeding forty-five percent (45%) shall require a public hearing before the Planning Commission.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Zoning Code: Supplement 29 | City Code: Supplement 61 Update 1).
Full Breakdown
Article 48, adopted in 2019 to add floor area ratio as its own development standard, applies to every Architectural Permit for a single-family dwelling in any zoning district, with three carve-outs: ground floor additions of any size, new homes or additions on lots under 5,000 square feet, and second-story additions of 100 square feet or less. Accessory dwelling units under Article 37 are excluded entirely. 3 defines "Gross Floor Area" as the total covered area of all floors measured to the outside of the stud walls, including attached garages, but excluding basements no more than 24 inches above grade, detached accessory buildings and ADUs, listed architectural features, attached ADUs and junior ADUs, and unenclosed ground-floor porches and patios. 4.
Violations & Fines
A single-family project built beyond the FAR/size threshold without the required Planning Commission review and findings is processed as a zoning violation, a public nuisance under Section 50.2, and an infraction under Section 50.5, carrying escalating fines of $100, $200 and $500 for a first, second and later violation of the same provision within a year, with each day of noncompliance a separate offense.
Frequently Asked Questions
What triggers Redwood City's mansionization review for a single-family home?
Are home additions exempt from the FAR review?
Does the mansionization rule apply to accessory dwelling units?
What must a large new house's design do to win Planning Commission approval?
Sources & Official References
Other rules in Redwood City
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