A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable ADU Builders Across San Francisco
Building an ADU in San Francisco means working with a city that has more layers of review than almost anywhere else in California. Between hillside seismic triggers, fire sprinkler rules, and party-wall notices, a project that looks simple on paper can stall for months if the contractor doesn’t know the local code path. That’s what we handle every day at Lodgewick ADU San Francisco. Our ADU Builders team has worked on tight lots from the Outer Sunset to Bernal Heights, and we’re ready to walk your property and give you a written price before any work begins.
Call (707) 760-0502 to schedule a site visit in San Francisco. A live person answers, day or night.
Why Lodgewick ADU San Francisco Is San Francisco’s Preferred ADU Builders Company
Russ Delmar leads our San Francisco location, and his job is to make sure every project runs on the commitments we put in writing: a price before work starts, a defined arrival window, a clean job site, and a written guarantee on every build. That’s The Kingswell Guarantee, and it applies to every ADU we build in San Francisco, from a studio over a Richmond District garage to a full detached unit in the Excelsior.
We know the difference between what San Francisco’s Planning Department will approve in the Sunset versus what it will push back on in a historic district like Liberty Hill. We know which hillside lots in Noe Valley and Twin Peaks need a geotechnical report before the first drawing is submitted. And we’ve handled enough garage conversions here to know that the biggest cost driver is rarely the square footage, it’s the mandatory foundation and sprinkler work that San Francisco requires that a flat-lot suburb never would.
Every crew member on your San Francisco job is background-checked and in uniform. You’ll always know who is on your property, and you’ll always have a direct line to our office if something needs attention.
ADU Design in San Francisco
ADU Design in San Francisco is where most projects get won or lost. The city’s planning review looks at floor area, rear-yard setbacks, historic resource status, and whether your lot sits in a liquefaction zone or on a slope over 25 percent. We start every design with a site walk and a check of the parcel’s zoning and geotechnical history, because San Francisco’s rules change block by block.
Site and Code Review Before Drawings
For a West Portal or Miraloma Park lot, the slope usually drives the structural design. For a flat-lot in the Bayview, the soil report and any history of liquefaction often control the foundation detail. We pull the property’s planning history, confirm whether the garage conversion will trigger a separate site permit from Public Works, and only then begin drawings. Skipping that step is how projects stall for six months.
What San Francisco Design Work Costs
Full ADU design, including as-built drawings, code analysis, and structural engineering, typically runs $12,000 to $28,000 in San Francisco depending on lot complexity and whether a variance is required. We give you that number in writing before any work starts. No price changes at the door.
Backyard ADU in San Francisco
Backyard ADU construction in San Francisco has to fit a constrained site: narrow access paths, shared lot lines, retaining walls, and neighbors close enough to hear every cut. We plan staging and material delivery around those constraints from the first site visit. That keeps the build cleaner and the neighbors more patient.
Access and Staging on Small Lots
On a recent Bernal Heights job, the crew converted a 1920s garage into a one-bedroom ADU. The site had a shared party wall with the uphill neighbor, so we issued the required 30-day notice and scheduled all drilling during permitted hours. Access was via a 7-foot-wide path, so we hand-carried materials and used a compact tracked skid steer to avoid damaging the retaining wall. The permit required full foundation underpinning and a new lateral load path, designed with the structural engineer before the Board of Appeals reviewed the hillside variance.
Backyard ADU Pricing
A backyard detached ADU in San Francisco generally runs $290,000 to $540,000 for a finished one-bedroom unit, including foundation, utility connections, and interior finishes. Hillside lots, soil problems, or historic-district review push the top of that range. A prefab unit from Abodu or Cover can shorten the on-site build time, but the site work, foundation, and permit path in San Francisco remain largely the same regardless of what arrives on the truck.
Trusted Brands We Service in San Francisco
We work with established ADU systems and materials including Abodu, Cover, and James Hardie siding and trim. That means we can spec a fully permitted backyard unit with a known lead time and a known material cost, which matters in a city where review timelines already stretch the schedule. We also handle Tuff Shed structures when the plan is a simple conditioned workspace or studio shell, and our crew knows how to prepare a San Francisco foundation for each system. Parts and material lead times are coordinated from our San Francisco Bay Area office, so you’re not waiting on a distributor three states away.
We don’t push one system over another. We match the unit to your lot, your budget, and the realities of your San Francisco permit path.
Common ADU Builders Problems We See in San Francisco Homes
- Garage conversions that trigger a mandatory seismic retrofit. This is the big one. San Francisco requires a foundation upgrade and a new lateral load path on many garage-to-ADU conversions, especially on pre-1940 homes. We budget for it from day one, so the number you sign is the number you pay.
- Fire sprinkler requirements the primary home never had. If the new ADU pushes the property over the occupancy threshold, San Francisco can require a residential sprinkler system in the ADU, and sometimes in the existing house too. That’s a five-figure scope item that no generic contractor thinks to mention.
- Party-wall notices and neighbor friction. On an attached ADU or a garage conversion sharing a wall, San Francisco requires written neighbor notification before certain work begins. We handle that paperwork and timing so the project doesn’t get stopped mid-frame.
- Hillside access that breaks the crane plan. A rear-yard ADU on a Twin Peaks or Russian Hill lot can’t always take a crane or a full-size concrete pump. We plan around narrow access with compact equipment and hand-carry where needed, and the quote reflects that access reality.
Pricing for ADU Builders in San Francisco, CA
Here’s what San Francisco homeowners should expect. A garage conversion ADU runs roughly $180,000 to $320,000 for a one-bedroom unit, and more if the seismic and sprinkler triggers hit. A backyard detached ADU runs $290,000 to $540,000. A junior ADU inside the existing home envelope runs $130,000 to $220,000. Prefab installation adds site work and foundation costs that mostly offset any savings on the structure itself, though schedule certainty is the real reason many San Francisco homeowners pick prefab.
The price we write is the price you approve. The Kingswell Guarantee puts that in writing before the first nail, and we don’t change it at the door. Call (707) 760-0502 to get a specific number for your lot. Estimates are free, and a live person answers.
We Also Serve Cities Near San Francisco
While this page focuses on San Francisco, our San Francisco crews also take on ADU projects in Daly City, Sausalito, Emeryville, and San Bruno. The permit path changes once you cross the county line, but the pricing discipline and written guarantee don’t.
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 Builders in San Francisco
Yes. In an RH-1 zone, a detached garage conversion to a second unit requires a building permit, and the project must post a neighborhood notification and wait through San Francisco’s mandatory 7-day review period before certain work can proceed. The conversion also triggers a Planning Department review for compliance with rear-yard and massing rules, and in some cases a structural review for seismic retrofit of the existing garage foundation. We handle the entire permit package, including the notice, so you don’t have to track deadlines. Call (707) 760-0502 for a site check on your specific garage.
For an attached ADU that shares a wall with a neighboring property, San Francisco requires a written notice to the adjacent owner at least 30 days before work begins on that shared wall. The notice describes the scope, the timeline, and the access needs. We prepare and deliver that notice on your behalf and document the date for the permit file. A missed notice is one of the most common reasons an attached ADU gets a stop-work order in dense neighborhoods like the Richmond or the Mission. We’d rather get it right the first time.
San Francisco waived most off-street parking requirements for ADUs when the unit is within a half-mile of a major transit stop or in a designated transit-rich area. In the Sunset, much of the district qualifies, but not every parcel does. You can’t assume the waiver applies just because you see a bus line a few blocks away. The planning review confirms the parcel’s transit status, and if the waiver doesn’t apply, you may need a variance. We verify this early in design so the parking question never surprises you at permit time.
A 1920s basement ADU in Noe Valley almost always requires a foundation upgrade to current seismic standards, typically a full or partial underpinning plus a new lateral load path connecting the existing house to the upgraded foundation. Noe Valley’s hillside lots add a slope-stability review, and depending on the block, the project may need a geotechnical report before structural drawings are approved. Budget for retrofit work to be one of the largest single line items in the job. We design it with the structural engineer and price it in writing before construction starts.
San Francisco limits construction noise to weekdays between 7 a.m. and 8 p.m. and weekends between 8 a.m. and 5 p.m., with stricter rules near residential properties. On a narrow Russian Hill street, where a crane or concrete pump would block the entire right of way, we schedule deliveries and pours within those hours and often need a Public Works encroachment permit for anything that occupies the street. The neighbor notification we send before work begins includes our planned work hours, which tends to keep things calmer on a block where houses sit close together. Call (707) 760-0502 and we’ll walk your street and tell you exactly how access will shape the schedule.
Call Lodgewick ADU San Francisco for a Written Estimate
If you’re planning an ADU in San Francisco, start with a site visit. We’ll walk your lot, look at access, check the zoning, and give you a written price. No pressure, no pricing games. The Kingswell Guarantee covers every build we do in San Francisco, from a garage conversion in the Sunset to a backyard unit in Bernal Heights. Call (707) 760-0502 to schedule your free estimate today. A live person answers, 24/7.
Written by Russ Delmar, Owner at Lodgewick ADU San Francisco, serving San Francisco homeowners with ADU design, garage conversions, and backyard units under The Kingswell Guarantee.
