ADU in San Francisco, CA
ADU Design & Permitting in San Francisco is a different animal than anywhere else in the Bay Area, largely because of what the city’s housing stock actually is: pre-1978 wood-frame Victorians and Edwardians sitting on unbolted mudsills, many with a ground-floor garage bay that was never meant to hold a finished living space. If you’re weighing an ADU on a San Francisco lot, the first conversation should be about what your building was built as, what the Soft Story database says about it, and what the permit set will require before a single wall moves. Call (971) 497-2402 to get that conversation started with someone who can read the data.
Why San Francisco Homes Are Different
The dominant San Francisco form, a Victorian or Edwardian row house with a garage punched into the ground floor beneath the living space, is the exact configuration the city’s Mandatory Soft Story Retrofit Ordinance (Chapter 34B) was written to address. That means a garage-to-ADU conversion here routinely pulls two structural engineers and two permit tracks into what a homeowner assumes is a straightforward room conversion. San Francisco has no sibling city where the mandatory retrofit program intersects with ADU work at this scale.
Climate compounds the structural question. The Sunset and Richmond districts, where much of this housing stock sits, live inside the summer fog belt: near-daily high humidity, condensation on slabs and stem walls, and finished spaces that never really dry out on their own. A converted garage in the Richmond needs a vapor barrier, rigid exterior insulation, and mechanical ventilation that would be overkill in Oakland or Berkeley. Then there’s the typical garage itself: a 7-foot ceiling, an unreinforced concrete slab, a mudsill that was never bolted, and no thermal break between the slab and the air you’re now calling a bedroom. All of it is solvable. None of it is optional if you want a permitted ADU that stays dry and doesn’t get flagged mid-permit by the retrofit database.
Our Main San Francisco Services
Two ADU paths dominate the phone calls we take from San Francisco homeowners: converting the existing garage, or building a new detached unit in the rear yard.
Garage Conversion ADU in San Francisco
A San Francisco garage conversion starts with a question most cities never ask: is this building flagged in the Soft Story Retrofit database? If it is, and the retrofit hasn’t been completed, the ADU permit application will surface that open compliance obligation, and the homeowner suddenly owes a full Tier 3 or Tier 4 seismic upgrade before the ADU can be finaled. That’s a $40,000 to $80,000 line item that has ended more than a few projects mid-design. Before we price a conversion, we check the database, and we show you what’s on it. The full scope of this work lives on Garage Conversion ADU in San Francisco.
New Detached ADU in San Francisco
A new detached ADU in San Francisco means yard work on lots that are often 25 feet wide with real setbacks and rear-yard open-space ratios enforced by Planning. On many San Francisco lots, the rear yard is the only place a detached unit fits, and the build has to work around a 40-foot lot depth, an existing garage at the rear property line, and neighbors’ windows 3 feet away at the side lot line. What gets built, and where, depends on the zoning envelope as much as on the budget. We cover that in full on New Detached ADU in San Francisco.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
ADU Design & Permitting in San Francisco
ADU Design & Permitting in San Francisco is the service that decides whether your project starts clean or starts behind. Most of our design work here begins with a San Francisco Planning and Building Department file review, a Soft Story database check, and a site measurement that tells us what the existing building will actually tolerate. The permit set we produce is the same document our own crews build from under ADU Design & Permitting, so nothing is drawn that we wouldn’t put our own framing crew up against.
Site Assessment
Signs you need it
You have an old garage, a rear yard, or an unfinished basement in a pre-1978 wood-frame San Francisco building and you want to know what the city will actually allow before you spend a dollar on drawings.
What it costs in San Francisco
Site assessment and feasibility work for an ADU in San Francisco typically runs $1,500 to $4,000, with the deliverable being a written scope and a written price for the design-and-permit package, not a verbal estimate.
How we do it
We pull the property’s Planning and Building records, check the Soft Story database, measure the site and the existing structure, and deliver a written feasibility memo with the zoning envelope, structural flags, and a fixed design-and-permit price attached.
ADU Design & Blueprints
Signs you need it
You’ve confirmed the lot can support an ADU and now need a permit-ready drawing set that San Francisco Building will actually accept, not a conceptual sketch from a draftsman who’s never filed in this city.
What it costs in San Francisco
Design and blueprint packages for a San Francisco ADU typically run $10,000 to $25,000, which includes architectural drawings, structural engineering, and the Title 24 energy documentation San Francisco requires at submittal.
How we do it
We draw the ADU to the lot’s actual zoning envelope, coordinate the structural engineering in-house with one written scope, and produce a permit set whose sheets line up with the way San Francisco DBI plan check reviews them.
Permit Application
Signs you need it
You have a permit set in hand, or you’ve been told by another designer that your ADU is ready to file, but you’re not sure which San Francisco permit track applies, what the fees will be, or what plan check will kick back.
What it costs in San Francisco
Permit application management for a San Francisco ADU typically runs $4,000 to $9,000, separate from city permit fees and school district impact fees, which San Francisco calculates on a per-square-foot basis.
How we do it
We run the application through the correct San Francisco track, respond to DBI plan check comments, and keep the paper trail on your side until the permit is issued and the job card is posted.
HOA & Zoning Compliance
Signs you need it
Your San Francisco property is in any of the city’s HOAs, a planned-unit development, or a historic or neighborhood character district that adds a layer of review beyond the ADU ordinance.
What it costs in San Francisco
HOA and zoning compliance review for a San Francisco ADU typically runs $2,500 to $6,000, which covers the zoning analysis, HOA submission documents where required, and the variance or discretionary-review filings if your lot needs one.
How we do it
We research the zoning district and any recorded CC&Rs, file the zoning worksheet, and submit exactly what San Francisco and the HOA ask for, in the order they ask for it, so plan check doesn’t stall.
What ADU Design & Permitting Costs in San Francisco
| Item | Typical range in San Francisco |
|---|---|
| Site Assessment & Feasibility | $1,500 - $4,000 |
| ADU Design & Blueprints | $10,000 - $25,000 |
| Permit Application Management | $4,000 - $9,000 |
How long does ADU design and permitting take in San Francisco?
Plan for 6 to 10 months from first site measurement to issued building permit. San Francisco DBI plan check and the Fire Department review can add time beyond a designer’s control, but a clean permit set shortens it. Call (971) 497-2402 for a realistic timeline on your specific project.
Will the San Francisco permit process require a structural retrofit on my garage?
If your building is flagged in the Mandatory Soft Story Program and hasn’t completed its retrofit, yes. The ADU permit application will surface the open compliance obligation, and the retrofit has to be resolved before final inspection. Call (971) 497-2402 for a written feasibility read before you commit.
Junior ADU & Interior Conversion in San Francisco
A Junior ADU or interior conversion in San Francisco is the most common ADU path on lots where the rear yard is too tight to build out, but the house itself has a garage, a big basement, or an underused ground-floor room to convert. In the Sunset and Richmond districts especially, the existing garage slab and the fog-driven moisture problem shape the whole design: a JADU carved out of a garage must handle condensation, ventilation, and a ceiling height that may be a few inches too low to meet code without a structural fix. That’s where our Junior ADU & Interior Conversion work starts.
Interior JADU
Signs you need it
You have a spare bedroom, office, or back-of-garage space with its own exterior door or an easy path to one, and you want a permitted JADU rather than an unpermitted in-law’s quarters.
What it costs in San Francisco
An interior JADU conversion in San Francisco typically runs $80,000 to $150,000 all-in, depending on whether a kitchenette line and a separate entrance already exist or have to be created.
How we do it
We design the unit to JADU code, file the permit set, build the kitchenette and the bathroom to San Francisco plumbing code, and deliver a finaled unit with documented photo records at every visit.
Attached Addition ADU
Signs you need it
Your San Francisco lot has a small side yard or a dead corner of the house that’s underused, and adding square footage against the existing garage or rear wall is the only way to make an ADU pencil out.
What it costs in San Francisco
An attached addition ADU in San Francisco typically runs $200,000 to $350,000 when built from the existing wall outward, with the final number driven by the foundation depth and the side-yard setback relief.
How we do it
We verify how close to the property line San Francisco will let us build, design the addition within that envelope, and run one contract from drawings through foundation, framing, and final inspection.
What Junior ADU & Interior Conversion Costs in San Francisco
| Item | Typical range in San Francisco |
|---|---|
| Interior JADU Conversion | $80,000 - $150,000 |
| Attached Addition ADU | $200,000 - $350,000 |
| Design & Permit Package (JADU path) | $8,000 - $18,000 |
Does a San Francisco JADU need its own entrance?
Yes. A Junior ADU in San Francisco requires a separate exterior entrance or an entrance from a shared corridor that is not the main front door of the house. Call (971) 497-2402 for a written scope that includes the entrance detail.
Can I convert part of my San Francisco garage into a JADU and keep the other part for parking?
Often yes, as long as the remaining garage space still meets San Francisco parking minimums and the JADU is separated by a rated wall and a weather barrier from the garage. Call (971) 497-2402 for a site check.
ADU Site Prep & Utilities in San Francisco
Site prep and utilities work in San Francisco runs into the city’s oldest problems first: unbolted mudsills, undersized overhead electrical services, 100-year-old clay sewer laterals, and rear yards that slope toward the house in a rain event. On a garage conversion or a new detached ADU, the first thing we check is what’s underground and what’s feeding the panel, because those two items set the real price of the job. This is the part of the project where ADU Site Prep & Utilities either gets done right once or gets redone after the inspector walks away.
Foundation & Grading
Signs you need it
Your San Francisco yard slopes toward the existing house, the garage slab has settled or cracked, or the new ADU footprint sits on ground that hasn’t been compacted since the 1920s.
What it costs in San Francisco
Foundation and grading for a San Francisco ADU typically runs $20,000 to $60,000, with the spread driven by whether the site needs a simple slab on grade or piers and a retaining wall.
How we do it
We bring a geotechnical read on the soil, then design and pour the foundation to the structural engineer’s spec, with drainage and slab insulation handled before the pad is ever poured.
Electrical Panel Upgrade
Signs you need it
Your San Francisco service panel is 100 amps or less, or it’s a 60-amp fused panel from the 1950s, and you can’t add an ADU subpanel without upgrading the service drop.
What it costs in San Francisco
An electrical panel upgrade for a San Francisco ADU typically runs $4,000 to $8,000, with the higher end covering a new 200-amp service, a mast, and the PG&E coordination that comes with it.
How we do it
We size the service to the ADU load calc, pull the San Francisco electrical permit, coordinate PG&E for the service drop, and land the subpanel so the ADU is isolated from the main house.
Plumbing Lateral
Signs you need it
Your San Francisco sewer lateral is original clay or cast iron, you’ve had backups before, and the ADU adds a bathroom and kitchen that the old line was never sized to carry.
What it costs in San Francisco
A plumbing lateral replacement or upsizing for a San Francisco ADU typically runs $8,000 to $20,000, depending on the trench length from the house to the city sewer main.
How we do it
We camera the line, determine where San Francisco requires the new lateral to tie in, and replace the pipe with the city inspector present at the backfill stage.
What ADU Site Prep & Utilities Costs in San Francisco
| Item | Typical range in San Francisco |
|---|---|
| Foundation & Grading | $20,000 - $60,000 |
| Electrical Panel Upgrade | $4,000 - $8,000 |
| Plumbing Lateral | $8,000 - $20,000 |
Does my San Francisco ADU need its own electrical panel?
Yes, San Francisco requires a dedicated subpanel for the ADU, fed from an upgraded main service if the existing one is undersized. Call (971) 497-2402 for a written load calculation before you commit to a panel size.
How deep do you have to dig for a San Francisco ADU foundation?
It depends on the soil and the structural engineer’s spec. Many San Francisco lots sit on sand or fill that requires deeper footings than the East Bay’s clay. Call (971) 497-2402 for a site-specific answer after a quick soil read.
Brands We Service in San Francisco
We specify and coordinate prefab and modular ADU systems from our brands, including Abodu, Cover, and Dvele units, within one written contract. These systems ship with factory-built shells, and our San Francisco crews handle the site work, utilities, and the finishing details that turn a dropped module into a permitted, finaled ADU. Turnaround from order to module delivery varies by manufacturer; the site prep and finishing schedule gets locked at signing.
Pricing for ADU in San Francisco, CA
| Service | Typical range in San Francisco |
|---|---|
| Site Assessment & Feasibility | $1,500 - $4,000 |
| ADU Design & Blueprints | $10,000 - $25,000 |
| Permit Application Management | $4,000 - $9,000 |
| HOA & Zoning Compliance | $2,500 - $6,000 |
| Interior JADU Conversion | $80,000 - $150,000 |
| Attached Addition ADU | $200,000 - $350,000 |
| Foundation & Grading | $20,000 - $60,000 |
| Electrical Panel Upgrade | $4,000 - $8,000 |
| Plumbing Lateral | $8,000 - $20,000 |
Two things push an ADU price up in San Francisco faster than anywhere else: a Soft Story retrofit obligation you didn’t know about, and a lot geometry that requires a custom foundation or a retaining wall. The single number that matters most is the one in writing before any work starts, because that’s the number we stand behind, not a ballpark. Every project we price in San Francisco carries a written price, a written scope, and a 365-Day Done Right Promise before we ask you to sign.
Neighborhoods We Serve in San Francisco
We work across San Francisco, from the fog-belt flats of the Sunset and Richmond to the hillier lots around Glen Park, Bernal Heights, and Noe Valley. Most crews arrive within a day of scheduling, and the site visit itself typically takes 60 to 90 minutes depending on what we’re measuring.
- Sunset District
- Richmond District
- Bernal Heights
- Noe Valley
- Glen Park
Service Area - Cities Near San Francisco
Our San Francisco crews also serve the cities that share the same PG&E service territory and the same building department geography: Daly City, CA to the south, South San Francisco, CA further down the Peninsula, and the East Bay cities of Alameda, CA and Berkeley, CA across the Bay.
Serving San Francisco, CA - Our Local Coverage Area
We’re based in the San Francisco area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About ADU in San Francisco
Site assessment and a written feasibility memo can happen within the week. The design and permitting phase typically takes 6 to 10 months, and construction follows once the permit is issued. Call (971) 497-2402 to get the process started with a written price, not a verbal estimate.
Yes. We check the Soft Story database before we price any garage conversion, and when a retrofit obligation appears, it becomes a named line item in the written scope, not a surprise discovered mid-permit. The retrofit and the ADU are designed and built as one coordinated set.
We work throughout San Francisco, from the Mission and Potrero Hill to the Marina and Excelsior. Lot geometry and building age vary across those neighborhoods, but the process is the same: written price, permit set, one contract, finaled ADU.
If you’re weighing an ADU in San Francisco, the first step is a site assessment that tells you what your lot and your building will actually allow, in writing, with a fixed price for the design and permit phase. Call (971) 497-2402 to schedule it.
What happens when you call
- 1A real person answersNo phone trees - talk to a local adu pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3We come out and measureLicensed & insured, at a time that suits you - the visit and the quote are both free.
- 4You get the price in writingLine-itemed, yours to keep, and nothing starts until you say go.
What San Francisco Customers Say
"Handled the whole planning process. We went to one hearing and that was it."
- Rowena C."Garage conversion finished on the drawings and close to the schedule. They were honest that the sewer connection was the unknown, and it was."
- Arjun D."The permit set and the build were one contract with one number. Our neighbours used two firms and spent a year watching them blame each other."
- Helena V.