Home Additions in Redwood City, CA
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Architectural Permits for Additions
Architectural Permit: required for new homes and for additions or exterior changes above the ground floor. Upper-floor additions of 100 sq ft or less, uncovered decks and balconies, and window changes are exempt. On sloping lots, it also applies to homes of 3,000 sq ft or more on slopes of 15% or more, and to any size on slopes of 30% or more. The Zoning Administrator usually decides without a hearing; homes over 3,000 sq ft and over 45% floor area ratio go to the Planning Commission. Two-story homes and second-story additions follow the citywide Residential Design Guide.
Addition Work
Plan Check, Trees and Sprinklers
Plan check usually takes 6 to 24 weeks depending on scope; the One Stop same-day review is available for some simple projects but not additions. Additions need 3 plan sets and new homes 4, with a soils report for new buildings, basements and hillside work. Additions over 500 sq ft need a Sequoia Union High School District fee receipt before permit. At least 65% of construction debris must be recycled, with documentation due within 90 days of final.
Protected trees: private trees over 38 inches in circumference (about 12 inches in diameter) need a permit before any work, usually processed in about 10 working days.
Sprinklers: Redwood City may require sprinklers for additions depending on scope under its 50% rule policy; we confirm with the Building Division during design.
1017 Middlefield Road, Redwood City, CA 94063
Building (650) 780-7350, pe*****@*********ty.org · Inspections (650) 780-7361 · Planning (650) 780-7234, pl******@*********ty.org
In-person counter Monday to Thursday, 10 a.m. to 4 p.m.; virtual Friday, 8 a.m. to 5 p.m. Permits are submitted through eTRAKiT, and a permit technician replies within about 5 business days. Inspections are booked by phone with two-hour arrival windows; a qualified person must be on site with the plans, permit and job card.
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Other Redwood City services: ADUs · Bathrooms · Kitchens · New Homes · Redwood City overview
Same service nearby: San Carlos · Atherton · Menlo Park
Redwood City Home Additions FAQ
Does a second-story addition need an Architectural Permit?
Yes, unless it is 100 sq ft or less.
Who decides?
The Zoning Administrator, usually without a hearing.
How long is plan check?
Usually 6 to 24 weeks depending on scope.
Is Emerald Hills in Redwood City?
No. Emerald Lake Hills is unincorporated and permitted by San Mateo County.