ADU & Home Additions in Redwood City
Add living space to your Redwood City property — from detached ADUs to second-story additions, designed to maximize your lot's potential.
How Much Does ADU & Home Additions Cost in Redwood City?
Detached ADUs in Redwood City. Garage conversions start lower at $100K-$180K. Additions vary by scope.
Every project is unique. We provide a fixed-price contract after your free consultation — no hidden fees, no cost-plus surprises. The price you agree to is the price you pay.
What to Know About ADU & Home Additions in Redwood City
Local building codes, neighborhood character, and permit requirements vary by city. Here's what Redwood City homeowners should know before starting a project.
- 01Redwood City processes ADU permits under California's streamlined 60-day review timeline, but complex projects with hillside overlay or engineering requirements may take longer
- 02Farm Hill and Woodside Plaza lots are typically 6,000-8,000 sq ft — large enough for a detached ADU while meeting the 4-foot rear and side setback requirements under state law
- 03Emerald Hills ADU projects often require geotechnical reports and engineered foundations due to hillside conditions; budget an additional $5,000-$15,000 for site-specific engineering
- 04Redwood City offers pre-approved ADU plans through San Mateo County's Regional ADU program, which can reduce permitting time by 2-4 weeks
- 05Utility connections for detached ADUs in Redwood City — including sewer lateral, water, and electrical — typically add $15,000-$30,000 to the project depending on distance from the main house
Our ADU & Home Additions Process
A clear, structured approach from your first call to final reveal.
Feasibility Assessment
We evaluate your property, zoning, and lot coverage to determine what's possible and what will deliver the best ROI.
Design & Engineering
Our architects create plans that maximize space, light, and livability while meeting all local building codes.
Permits & Approvals
We navigate the full permitting process — city planning, building department, and utility coordination.
Construction
Our experienced crew builds your ADU with the same quality standards as our luxury home remodels.
Inspection & Handover
We manage all inspections, obtain the certificate of occupancy, and walk you through your completed ADU.
ADU & Home Additions in Redwood City: FAQ
Answers to common questions from Redwood City homeowners.
Under California state law, you can build a detached ADU up to 1,200 sq ft on most Redwood City lots, regardless of lot size. You can also build a Junior ADU (JrADU) up to 500 sq ft within your existing home in addition to the detached unit. Garage conversions are also permitted without regard to lot coverage limits.
Redwood City follows California's 60-day ADU permit review timeline for most projects. With plan preparation and any required engineering, the total pre-construction phase is typically 3-5 months. Construction takes 5-8 months for a detached ADU. Total timeline from initial design to move-in is approximately 10-14 months.
Yes. California law permits ADU rentals in all residential zones. Redwood City allows long-term rentals of 30+ days. Short-term vacation rentals under 30 days are subject to the city's short-term rental regulations. Many Redwood City homeowners use ADUs for family members or as home offices rather than rentals.
A well-built ADU in Redwood City typically adds $200,000-$450,000 in property value — often exceeding construction costs. The rental income potential ($2,500-$4,000/month for a 1-bedroom unit) further enhances the investment. ADUs are especially valuable in Redwood City's competitive housing market.
Yes. Garage conversions are one of the most cost-effective ADU options in Redwood City, typically costing $100,000-$180,000. California law prohibits cities from requiring replacement parking when converting a garage to an ADU. We reinforce the existing structure, add insulation, plumbing, and finishes to create a comfortable living space.
No. California eliminated owner-occupancy requirements for ADUs permitted after January 1, 2020. You can build an ADU on your Redwood City property and rent both the ADU and the primary home. However, owner-occupancy is still required for Junior ADUs (JrADUs).
More Services in Redwood City
Explore our other design-build services available in Redwood City.
ADU & Home Additions in Nearby Cities
Ready to Start Your Redwood City ADU & Home Additions?
Book a free in-home consultation. We'll discuss your vision, walk through your space, and provide a detailed fixed-price estimate — no pressure, no obligation.