A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateTrusted ADU Builders for San Francisco Homeowners
Adding an accessory dwelling unit (ADU) is the fastest way to gain usable square footage on a San Francisco lot without moving. But anyone who has watched an ADU project go sideways knows the real cost isn’t material or labor, it’s a builder who stops answering the phone. Lodgewick ADU Builders in San Francisco was founded in 2010 as part of the Kingswell family of home-service companies, and we run every project under The Kingswell Guarantee: a written price before work begins, a defined arrival window, a clean job site, and a written 365-Day Done Right Promise on every build. If it isn’t right, we come back and make it right. Call (707) 760-0502 to talk to a live person, day or night.
Key Takeaways
- Written price first: You get a line-item quote before any work starts. No change orders at the door.
- 365-Day Done Right Promise: If the work fails within a year, we return and fix it, free.
- Real pricing in San Francisco: Detached ADUs run roughly $250,000 to $450,000; garage conversions typically $120,000 to $220,000; JADUs $80,000 to $150,000.
- Live person answers 24/7: No voicemail loop, no chatbot. You call, a person picks up.
- We know this city: Sunset District setbacks, Bernal Heights slope issues, Richmond District lot dimensions. We’ve built on all of it.
ADU Construction
ADU Construction is the full build-out of a secondary housing unit on a property you already own, whether that means converting a garage, building a detached structure behind the house, or splitting off part of the main home into a separate apartment. In San Francisco, our ADU Construction work typically lands between $120,000 and $450,000 depending on whether you’re converting existing space or pouring new foundation, and site conditions like zero-lot-line setbacks or hillside access can push the number higher. We handle permits, plans, foundation, framing, electrical, plumbing, drywall, and finish work, all under one written contract.
The Kingswell Way on a San Francisco Job Site
Every Lodgewick ADU San Francisco crew member is background-checked and uniformed, so you always know who is walking onto your property. We state the price before the work, show up in the arrival window we gave you, and leave the job site cleaner than we found it.
What Construction Looks Like Week to Week
Most San Francisco ADU construction takes 4 to 8 months from permit pull to final inspection. You’ll get a written schedule up front, and your project lead calls you with updates rather than making you chase us down.
Detached ADU
A Detached ADU is a fully separate living unit built from the ground up in your rear yard, with its own foundation, walls, roof, kitchen, bath, and address. A detached build in San Francisco generally costs $250,000 to $450,000, with the final number driven by soil conditions, how much foundation work the slope requires, and whether utilities need to be trenched from the street or spliced from the main house. Lodgewick ADU San Francisco manages the whole thing: design, engineering, permits, foundation, framing, utilities, and finishes.
Backyard Setbacks and San Francisco Zoning
San Francisco has some of the strictest rear-yard and side-yard setback rules in the Bay Area, and a detached unit usually has to stay within specific height and lot-coverage limits. We measure the actual lot before we quote, so the price you see reflects what the city will actually approve, not a guess.
Prefab vs. Site-Built Detached Units
Depending on the lot and timeline, we may recommend a site-built detached ADU or a panelized option like Plant Prefab, which can shorten framing time by weeks. The written price covers whichever path we agree on, before we start.
JADU
A JADU, or Junior Accessory Dwelling Unit, is an ADU of 500 square feet or less built within the footprint of an existing home, typically a garage conversion, a basement conversion, or a portion of the main house that gets its own entrance, kitchenette, and bath. In San Francisco, JADUs are often the most affordable path to rental income or family housing and usually run $80,000 to $150,000, depending on how much plumbing and electrical work the existing space needs. Lodgewick ADU San Francisco handles the entire conversion under The Kingswell Guarantee, with the written price before work starts.
The JADU Advantage in San Francisco
Because a JADU works within existing walls, you avoid the cost and delay of new foundation and exterior structure. San Francisco’s ADU ordinance has made garage and basement JADUs easier to permit than ever, and we’ve helped homeowners in the Sunset and Excelsior Districts turn underused garages into legal, rentable units.
What Separates a Cheap JADU from a Legal One
We see JADUs done badly everywhere in the city: no separate electrical subpanel, no proper egress window, ventilation that doesn’t meet code. Our builds come with a written guarantee and pass city inspection before you write the final check.
ADU Plans
ADU Plans are the architectural and engineering drawings that the San Francisco Department of Building Inspection requires before any permit can be issued for an accessory dwelling unit. Most San Francisco homeowners spend $8,000 to $25,000 on ADU Plans alone, depending on the complexity of the lot and the number of revisions the planning department requires. Lodgewick ADU San Francisco includes plan preparation in your written quote, and we walk the plans through the city’s permitting queue rather than handing you a PDF and wishing you luck.
Why San Francisco Plan Review Takes Patience
San Francisco plan review is notoriously slow, and small errors in a drawing set can add months to the timeline. Our design team has worked through enough DBI submittals to know which details get kicked back, and we draft to the city’s checklist from day one.
What You’ll See Before You Sign
You’ll receive a full drawing set: site plan, floor plan, elevations, structural details, electrical, plumbing, and title 24 energy calculations. Every page is reviewed with you line by line before we submit, so there are no surprises when the permit comes back.
ADU Contractor
An ADU Contractor is the licensed general contractor who carries the build from permit to completion, including hiring and managing the electrical, plumbing, framing, roofing, and finish trades. When you hire Lodgewick ADU San Francisco as your ADU Contractor, you get one written contract, one point of contact, and one phone number where a live person answers 24/7. You don’t coordinate subcontractors, and you don’t get told to “work it out with the electrician.” That’s our job.
Why One Written Contract Matters
Most ADU horror stories start when the homeowner has three different contracts with three different crews and no one owns the schedule. Your Lodgewick contract covers every trade, every material, and every permit fee, so when the framing crew is late, the delay is our problem to fix, not yours.
Subcontractor Standards on Every Job
The crews on your project are background-checked and uniformed, and the site lead reviews the written scope with you before that trade starts. If a subcontractor leaves the site messy or skips a step, it gets corrected before we move to the next phase.
ADU Design
ADU Design is the process of shaping the unit to fit your lot, your budget, and how you actually want to use the space: rental income, aging parents, adult kids, a home office, or all of the above. In San Francisco, thoughtful ADU design can be the difference between a garage conversion that rents for $2,200 a month and one that sits empty because the layout feels cramped and dark. Lodgewick ADU San Francisco includes design consultation in your written quote, and we bring 15 years of Bay Area lot experience to every drawing.
Designing Around the Typical San Francisco Lot
The city’s long, narrow lots, 25-foot widths, and steep backyards make ADU placement a real puzzle. We’ve designed units for flat Sunset District lots, sloped Bernal Heights backyards with retaining walls, and Richmond District side yards where every inch counts. We also serve nearby communities through our ADU Builders in Daly City.
Materials and Prefab Options Worth Considering
For the right project, we bring in trusted prefab manufacturers like Boxabl and Plant Prefab, which can deliver a partially assembled shell and cut framing time substantially. We’ll compare factory-built vs. site-built costs for your lot in writing, so you can choose with real numbers in front of you.
Backyard ADU
A Backyard ADU is a detached accessory dwelling unit placed in the rear yard of a single-family home, usually where a garden, lawn, or unused storage area sits today. In San Francisco, a backyard ADU typically costs $250,000 to $450,000 once you account for foundation, utility trenching, framing, finishes, and the city’s permitting process. Lodgewick ADU San Francisco has built backyard units in neighborhoods across the city, and every one started with a written price and ended with a written 365-Day guarantee. For projects just north of the Golden Gate, we also connect homeowners with ADU Builders in Sausalito.
What Happens to Your Yard
You’ll lose usable yard space, but a well-planned backyard ADU leaves enough room for a patio or garden and can actually make the lot feel more intentional. We walk the property with you before design starts to plan access paths, privacy screening, and any fence work the city requires.
Getting Utilities to the Back of the Lot
Water, sewer, gas, and electrical all have to reach the new unit, and trenching through a San Francisco backyard often means navigating old clay sewer lines and tree roots. We include the full utility scope in the written quote, so there’s no mid-project surprise when the trenching starts.
Brands We Service
Lodgewick ADU San Francisco has hands-on experience with several leading ADU and building-materials brands, and we’ll match the right one to your lot, budget, and timeline. Boxabl’s folding-panel units can work well for compact backyard builds where crane access and a simple foundation make factory delivery practical. Plant Prefab’s panelized wall and floor systems are a strong fit for San Francisco lots where a faster framing schedule matters and where we want precision dimensions to meet the city’s tight setback rules. Across the Bay, we also work with our ADU Builders in Emeryville.
James Hardie fiber cement siding is one of the most common exterior finishes we install on both detached and attached ADUs across the city, because it stands up to wet Richmond District winters and dry Excelsior summers better than wood lap. Whether you have a specific brand in mind or you want our recommendation, we’ll put the options in writing before the job starts.
Signs You Need a Pro Right Now
- You’re renting out an unpermitted unit. San Francisco has been expanding its ADU legalization programs, but renting an unpermitted space still puts you at risk of code enforcement, insurance denial, and tenant disputes. A legal, permitted ADU with a written guarantee is a different asset class entirely.
- Your garage was “converted” by someone who never pulled permits. We see this constantly: a garage conversion with one circuit of electrical, no insulation, and a bathroom drain that ties into a floor drain. The city can flag it during a property sale or remodel, and the fix is often a full gut.
- Your lot has an unusual shape or steep grade. Homes in Noe Valley, Glen Park, and Twin Peaks sit on serious slopes. Building on a hillside requires retaining walls, engineered foundations, and drainage planning. Guessing at that scope is how budgets blow up.
- You got a quote that seems too cheap to be real. If a San Francisco ADU quote comes in under $100,000 for a detached build, something is missing from that scope. We’ll show you our line items and explain exactly what the other bid is leaving out, for free.
- A previous contractor stopped returning your calls mid-project. That’s not a scheduling problem, it’s a trust problem. The Kingswell Guarantee exists for this exact situation: a written promise, in hand, before a single nail gets driven.
Our Process, Step by Step
- 1
Initial call and property walk. You call (707) 760-0502 and reach a live person, not a voicemail queue. We schedule a site visit, walk the lot with you, measure the yard, and talk through what you’re trying to accomplish: rental income, family housing, a workspace, or all three.
- 2
Written scope and price. You receive a written line-item price covering plans, permits, materials, labor, and finish work. This is the price. It doesn’t change at the door. If we find an unknown condition during construction, we document it, explain it, and get your written sign-off before doing anything different.
- 3
Design, plans, and permit submittal. Our design team produces the drawing set and submits it to the San Francisco Department of Building Inspection. We track the permit through every round of review and make revisions until it’s approved.
- 4
Construction with a defined arrival window. Your crew shows up in the window we committed to, in uniform, background-checked. The site lead walks you through what’s happening each week, and the job site stays clean, no debris piles left overnight without a plan.
- 5
Final walkthrough and written guarantee. Before we call the project done, we walk the entire unit with you and create a punch list of anything and everything you want addressed. Once it’s signed off by you and the city, you receive the written 365-Day Done Right Promise: if it fails within the year, we come back and make it right, free.
How Much Does ADU Builders Cost in San Francisco?
ADU builds in San Francisco fall into three realistic brackets. A JADU inside the existing home footprint usually runs $80,000 to $150,000. A garage conversion ADU typically lands between $120,000 and $220,000 depending on whether the garage has a slab foundation or needs structural reinforcement and new drainage. A detached backyard ADU is the most expensive path at $250,000 to $450,000, driven by foundation work, utility trenching, and the city’s permitting and inspection fees. These are honest ranges based on our own build history in the city, not marketing numbers designed to get you on the phone.
What changes the price? Lot slope, soil condition, the age of the main home’s electrical panel, sewer line location, and how far utilities need to run. Prefab options like Boxabl or Plant Prefab can reduce framing labor but may add crane and delivery logistics. The best way to avoid overpaying is to compare written line-item quotes, not verbal ballparks. Every free estimate from Lodgewick ADU San Francisco includes the full written scope, and the number on that page is the number we build for. Call (707) 760-0502 to start.
Our Service Area Near San Francisco
Lodgewick ADU San Francisco serves homeowners throughout the city and surrounding Bay Area communities, including Oakland, Hayward, Daly City, San Bruno, South San Francisco, San Rafael, Richmond, and San Leandro. If you’re in San Francisco proper, our team is already familiar with your neighborhood’s lot patterns and planning expectations. Call (707) 760-0502 and we’ll schedule a property walk. For general information about our work, visit our home page or learn more about ADU Builders in San Francisco.
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.
Frequently Asked Questions About ADU Builders in San Francisco
An ADU builder is a contractor who specializes in designing, permitting, and constructing accessory dwelling units on residential lots. We handle everything from initial site assessment and drawings to foundation, framing, utilities, and interior finish work. A good ADU builder gives you one written contract that covers the entire project.
Most ADU projects in San Francisco take 4 to 8 months, with plan review at DBI often consuming 3 to 6 months of that timeline. JADUs and garage conversions are usually faster than detached new construction because there’s less foundation and framing work. We give you a written schedule before you sign, and we update it in writing if anything changes.
Expect $80,000 to $150,000 for a JADU, $120,000 to $220,000 for a garage conversion, and $250,000 to $450,000 for a detached backyard ADU. Your final number depends on lot conditions, utility routing, and finish choices. We provide a written line-item quote before work begins, so you always know your number. Call (707) 760-0502 for your free estimate.
Yes. We have hands-on experience with Boxabl, Plant Prefab, Tuff Shed, and related systems, and we’ll recommend a factory-built or panelized approach when it saves you time or money on your specific lot. The written quote includes the cost of whichever path we agree on.
If your existing ADU has a leak, electrical problem, or structural issue, call (707) 760-0502 and a live person will answer. We prioritize urgent repairs and send a uniformed, background-checked technician to assess the problem. The 365-Day Done Right Promise covers any work we performed that fails within the guarantee period.
Every project from Lodgewick ADU San Francisco includes the written 365-Day Done Right Promise. If the work isn’t right within one year, we return and make it right at no charge. This warranty is delivered in writing before construction starts, not buried in fine print after you’ve paid.
Start by gathering your property’s parcel number, any old plans or surveys you have, and your goals for the unit: rental income, family use, or resale value. Then call (707) 760-0502 for a free site walk and written estimate. We’ll handle the rest, including permits and city inspections.
Schedule Your ADU Builders Service in San Francisco Today
The next step is a phone call to (707) 760-0502. We’ll walk your lot, answer your questions, and put a written price in your hands before any work starts. The 365-Day Done Right Promise comes with it, in writing. Call today and see what a real guarantee feels like.
Written by Russ Delmar, Owner at Lodgewick ADU San Francisco, serving San Francisco since 2010.
