Home Additions in San Carlos, CA
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Objective Standards for Additions
Compliance Review: since December 13, 2023, San Carlos reviews single-family projects against objective design standards. A staff-level Compliance Review, decided by the Community Development Director, applies to residential improvements in RS zones, and projects that meet the standards are approved with no public hearing. Additions inside the existing building envelope are exempt. Requests to deviate from the standards go to the Planning and Transportation Commission at a noticed hearing, and the applicant or adjacent and facing neighbors can request Director review within 10 days of a staff decision.
Published plan-check targets: kitchen or bath remodel 3 to 5 days; single-story addition 2 to 4 weeks; second-story addition 3 to 5 weeks; new single-family home 4 to 6 weeks; rechecks 10 days to 2 weeks.
Addition Work
Hillsides, Sprinklers and Trees
Hillside Overlay (average slope of 20% or more): 35 feet overall height, with downhill street-facing elevations limited to 20 feet plus a 5-foot step-back; created slopes no steeper than 30%; at least 35% of the lot left natural; driveways at an 18% average grade or less. Wildland-urban interface construction rules apply south of San Carlos Avenue and west of Alameda de las Pulgas.
Fire sprinklers: required in residential reconstruction of 2,500 sq ft or more, such as replacing over 50% of the foundation or exterior wall framing, and when a one-story home becomes a two-story home over 2,500 sq ft. The Redwood City Fire Department’s Bureau of Fire Prevention administers the fire code for San Carlos.
Trees: “significant” trees 11 inches or more in diameter at 54 inches, redwoods at 15 inches, and heritage and required trees need a permit to remove or prune.
School fees: Sequoia Union High School District collects fees for itself and the elementary district for projects over 500 sq ft, and certifies payment before the permit is issued.
600 Elm Street, San Carlos, CA 94070
Building (650) 802-4261, bu******@*************os.org · Planning (650) 802-4263, pl******@*************os.org (first floor; counter Monday to Thursday, 9 a.m. to noon by appointment, closed Fridays)
Submittals are digital only through the City’s Tyler EP&L Customer Self-Service portal. Building counter hours and inspection scheduling are by appointment, so call ahead. Construction hours: 8 a.m. to 5 p.m. weekdays and 9 a.m. to 5 p.m. Saturdays; no work Sundays or holidays.
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Other San Carlos services: ADUs · Bathrooms · Kitchens · New Homes · San Carlos overview
Same service nearby: Belmont · Redwood City · Menlo Park
San Carlos Home Additions FAQ
Is there a hearing for a San Carlos addition?
Not if it meets the objective standards; staff approves it through Compliance Review.
How long is plan check for a second-story addition?
The City targets 3 to 5 weeks.
When are sprinklers required?
For reconstruction of 2,500 sq ft or more, or a one-story home becoming a two-story home over 2,500 sq ft.
Are additions inside the existing envelope reviewed?
They are exempt from Compliance Review.