Serving the Bay Area
ADU Construction in San Francisco That Gets Built, Permitted, and Rented
Bayside Home Builders handles the full process, from SF Planning approvals to final inspection, so your accessory dwelling unit adds real income or space without the runaround.
adu project · San FranciscoSan Francisco ADU Projects Stall for Predictable Reasons
The demand for ADUs in SF is real, and the city has made approvals easier in recent years. But homeowners still run into the same problems: underestimating total cost, hitting unexpected conditions inside older walls and foundations, and working with contractors who are not fluent in SF's specific permitting requirements.
What you are living with
A stalled permit, a surprise soft-story retrofit requirement, or a contractor who underbid the job and disappears mid-project costs you months and real money. In a city where construction costs routinely run $200,000 to $300,000 for an ADU, getting the estimate wrong by 20 percent is not a rounding error.
What you get instead
We give you an honest scope and budget before you commit, including a clear look at what your specific lot, structure, and utility connections are likely to require. We handle the SF permitting process in-house and stay on the job through final inspection. No handoffs, no surprises handed off to you.
Our Recent Work
Accessory Dwelling Units Built to Code, Start to Finish
An ADU adds a fully independent living space to your property, a detached backyard cottage, an attached unit, or a converted garage. We handle every piece of it: design, permits, foundation, framing, MEP rough-ins, finishes, and final inspection. One contractor accountable for the whole project.
Site Assessment and Feasibility Review
Before you spend money on drawings, we walk the property, check setbacks, utility access, and lot coverage limits so you know what is actually buildable on your specific parcel.
Custom Design and Construction Documents
Our in-house design team produces permit-ready architectural and structural drawings sized to your lot and matched to your goals, whether that is a rental unit, space for family, or a home office.
Permit Procurement
We prepare and submit the full permit package and manage agency responses, corrections, and resubmittals. You do not have to track down planners or decode comment letters.
Foundation and Structural Work
Depending on the ADU type, this means a new concrete foundation, reinforced slab, or engineered upgrades to an existing structure. All work is inspected and documented.
Full MEP Systems
Electrical panel upgrade or sub-panel, new plumbing supply and waste lines, HVAC or mini-split installation, and smoke and CO detection, all pulled under separate trade permits and signed off by inspectors.
Interior Finishes and Final Inspection
Kitchen, bath, flooring, doors, and trim completed to a livable, rentable standard. We walk the unit with the building inspector and hand you a passed final inspection card before we close out the job.
Why Homeowners Choose Bayside Home Builders for Their ADU
A lot of contractors will frame an ADU. Fewer can carry it from raw dirt to a certificate of occupancy without the homeowner having to manage three separate companies. Here is what sets our process apart.
Licensed Design-Build Under One Roof
We are a CA CSLB licensed, bonded, and insured contractor with in-house design staff. Your architect and your builder are on the same team from day one, which eliminates the finger-pointing that derails projects when design and construction are separate contracts.
Permit Experience Across Multiple Jurisdictions
ADU permit requirements vary significantly from one municipality to the next. We have worked through the planning and building departments in multiple cities and know how to prepare packages that move through review without unnecessary back-and-forth.
Family-Owned with Direct Superintendent Oversight
As a family-owned company, the people who sold you the project are the same people managing it in the field. You reach a decision-maker directly, not a call center, when you have a question mid-construction.
Transparent Scope Before You Sign
We provide a written scope of work that breaks out site work, structural, MEP, and finishes so you know what is included and what would constitute a change order. Vague contracts are the leading cause of ADU budget overruns.
What our clients say
We recently had our kitchen remodeled by Bayside Home Improvement, and overall, we’re really happy with how everything turned out. The kitchen looks completely refreshed, and the space is much more pleasing to walk into. The team was professional…
I had the pleasure of working with Samuel on my kitchen and home remodel and I am thrilled about how it came out. His team was great in getting the designs together and listening to our ideas and interests. We went with an open layout design which…
How an ADU Project Works With Us
ADUs involve more moving parts than a typical remodel. Here is the honest sequence of how we take a project from your first call to a finished, permitted unit.
Step 1: Site Visit and Feasibility Conversation
We schedule a visit to your property, review your parcel data, discuss what type of ADU fits your goals and your lot constraints, and give you a realistic picture of timeline and process before any money changes hands.
Step 2: Design, Pricing, and Contract
We produce a design that meets local zoning and building code requirements and prepare a fixed-scope proposal. Once you approve the design and sign the contract, we finalize construction documents and submit for permits.
Step 3: Permit Processing and Pre-Construction
We manage the permit queue and respond to any agency comments. While permits are in review, we lock in subcontractors and order long-lead materials so construction starts without delay once approvals are in hand.
Step 4: Construction, Inspections, and Closeout
We build to the approved plans with all required inspections scheduled and passed at each phase. At completion, we walk the unit with you, address any punch list items, and hand over your certificate of occupancy and all warranty documentation.
What Adu Costs
San Francisco permits ADUs under state-streamlined rules, but the city's dense housing stock, hillside lots, and SF Planning review process make every project different.
Attached ADU
Converting or adding living space within the existing footprint.
Garage conversion
Turning an existing garage into a permitted dwelling.
Detached DADU
A standalone backyard cottage, built to code and permitted.
SF Planning requires a building permit for any ADU construction, and the complexity of your existing structure, whether a garage conversion, basement unit, or detached backyard build, directly affects design scope and permit timeline. The city sets a minimum of 220 square feet and a maximum of 800 to 1,000 square feet depending on unit type, so confirming what your lot and building can legally support is the first step before any cost discussion.
ADU Contractors Serving San Francisco
San Francisco has some of the most permissive ADU rules in California, but the city's permitting process, older housing stock, and dense lot conditions add real complexity. We build attached, detached, and garage-conversion ADUs across SF and help you navigate the process from planning through final inspection.
Permits & review
SF Planning and the Department of Building Inspection both touch ADU applications. The city offers an ADU fast-track program for eligible projects, which can compress the timeline compared to standard review. Budget realistically: published permit and construction costs in San Francisco typically start around $125,000 and commonly run $200,000 to $300,000 depending on scope, site conditions, and finishes. We pull permits and manage the process directly, so nothing falls through the cracks.
Housing stock
Most San Francisco neighborhoods are built out with Victorian, Edwardian, and mid-century homes on tight lots. Garage conversions, basement conversions, and additions above existing structures are the most common ADU paths here. Detached ADUs are possible on qualifying properties. Minimum size is 220 square feet, and single-family properties have the right to build an ADU of at least 800 square feet with a 16-foot height limit and four-foot side and rear yard setbacks. Older foundations, aging utilities, and hillside sites can all affect cost and schedule.
Areas we serve
We serve San Francisco and the surrounding Bay Area. If you are in the Sunset, the Richmond, Bernal Heights, Noe Valley, or the Excelsior, we have worked on homes in neighborhoods like yours and understand the typical lot sizes, utility conditions, and planning considerations you will face.
Common questions
Can I build an ADU in San Francisco?
Yes, and San Francisco's rules are more permissive than most Bay Area cities. Single-family homeowners have the right to build at least one ADU up to 800 square feet with a 16-foot height limit. Multifamily buildings can add ADUs converted from existing non-livable space. SF Planning has a fast-track program for qualifying projects, which can cut approval time significantly compared to standard permit review. The catch is that SF's construction costs and permitting complexity are among the highest in the state, so the planning and documentation work matters.
How much does it cost to build an ADU in San Francisco?
Budget $200,000 to $400,000 for most detached or new-construction ADUs in San Francisco. Garage conversions and basement conversions typically run $150,000 to $250,000 depending on structural work, waterproofing, and utility connections. SF's own planning department notes that material and labor alone typically start at $125,000 for a permitted unit. Design fees, engineering, permits, and utility hookup fees add to that total. A realistic all-in number for a finished, code-compliant detached ADU in SF is $250,000 to $350,000 for most projects.
How long does it take to build an ADU in San Francisco?
Plan for 12 to 24 months from start to certificate of occupancy. SF Planning's ADU fast-track program can shorten the permit approval phase to 4 to 6 months for qualifying projects. Design and engineering typically take 2 to 4 months before you even submit. Construction on a detached ADU runs 4 to 8 months once you have permits in hand. Garage and basement conversions can move faster on the construction side, but utility work and inspections still take time. Complex sites or projects that need variances will run longer.
What are the drawbacks of building an ADU in San Francisco?
The main ones are cost, time, and tenant protections. Construction costs in SF are genuinely high, and the permit process requires patience. Once you rent the ADU, San Francisco's rent control and just-cause eviction rules apply in many situations, which limits your flexibility as a landlord. Some homeowners also underestimate utility upgrade costs, especially when the existing electrical panel or sewer lateral needs work to support a second unit. None of these are reasons to avoid building, but they are things you should price and plan for upfront.
What size ADU can I build in San Francisco?
For single-family homes, SF allows at least one ADU of 800 square feet for a one-bedroom unit or 1,000 square feet for a two-bedroom unit. The minimum habitable size is 220 square feet, and ceilings must be at least 7.5 feet high. Detached ADUs follow the same size limits. California state law also allows JADUs (Junior ADUs) up to 500 square feet carved out of existing living space. If you want to go larger, the specific zoning for your parcel determines what's possible, and some lots can accommodate more than the baseline rules allow.
Can you build a 1,500 square foot ADU in California?
State law sets the baseline ADU size at 1,200 square feet for most new construction ADUs in California, though local jurisdictions can allow more. San Francisco's local rules cap most ADUs at 800 to 1,000 square feet depending on bedroom count, but your specific zoning district may allow larger units. If you need more space, a Junior ADU combined with a standard ADU is one strategy, since some properties can have both. The right answer depends on your lot size, existing structures, and zoning, which is why a site review is the first step.
Does Bayside Home Builders handle ADU permits in San Francisco?
Yes. We manage the full scope, including design coordination, engineering, SF Planning submission, DBI permit applications, and construction through final inspection. San Francisco has specific ADU rules around setbacks, unit size, parking, and tenant noticing that are different from other Bay Area cities. We work in SF regularly and know where projects get held up and how to keep them moving. If you have a property in San Francisco and want an honest assessment of what your ADU would cost and how long it would take, contact us for a site consultation.
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