Frequently Asked Questions - ADU in San Francisco, CA
Straight answers to the questions San Francisco homeowners ask us most about accessory dwelling units, from real permit timelines to what a garage conversion actually costs here. If you don't see your question, call (831) 272-7212 and we'll talk it through.
Pricing & Cost FAQs
In San Francisco, a detached ADU typically runs $350,000 to $550,000, while garage conversions land between $180,000 and $300,000 depending on foundation work and utility runs. Attached additions fall in the $250,000 to $400,000 range. These figures reflect current San Francisco labor rates, seismic requirements, and the city's notoriously detailed planning review. What moves the number most is whether you're converting existing square footage or building new, plus site conditions like slope and soil. We put every price in writing before any work starts, so you'll see the full breakdown before you commit. Call (831) 272-7212 for a free estimate on your specific lot.
A garage conversion is almost always the cheapest path to an ADU in San Francisco, typically $180,000 to $300,000. The structure already exists, so you skip foundation, framing, and roofing costs that drive new construction up. What you'll still pay for: seismic retrofitting to meet San Francisco code, insulation, electrical service upgrades, and plumbing runs. A junior ADU, which is carved out of existing house square footage, can run lower still, often $120,000 to $180,000, because it may share utilities with the main house. Keep in mind that cheap doesn't mean fast in San Francisco; even a conversion goes through full permit review. Call (831) 272-7212 and we'll price out your realistic options.
Expect to pay $180,000 to $300,000 to convert a garage into a legal ADU in San Francisco. The spread depends on whether your garage sits on a flat slab or needs structural work, whether sewer and electrical lines are close by, and whether the city requires you to preserve off-street parking. San Francisco's soft-story rules and soil conditions in neighborhoods like the Sunset and Bernal Heights can add foundation costs that other cities don't deal with. Every garage conversion we quote includes a written line-item breakdown before work begins, so there are no surprises mid-project. For a free estimate on your garage, call (831) 272-7212.
San Francisco ADUs cost more because the city layers on seismic requirements, strict energy codes, planning review, and some of the highest labor rates in the country. A project that might clear permits in weeks in Sacramento can take months through San Francisco's Department of Building Inspection. Hillside lots, common in Noe Valley and Twin Peaks, often require retaining walls and special foundations. Materials cost roughly the same as elsewhere, but the labor to install them is priced for Bay Area wages. The tradeoff is that a well-built ADU in San Francisco holds its value and rents at a premium. We'll show you exactly where your money goes in a written quote. Call (831) 272-7212.
Yes, estimates are free. We come out, look at your lot or garage, talk through what's feasible under San Francisco code, and put together a written proposal with real numbers. You get a line-item price before any work starts, and that price is the price. No vague allowances, no change orders you didn't ask for. If you're still deciding between a garage conversion and a backyard unit, we'll price both so you can compare. It takes about an hour of your time and commits you to nothing. Call (831) 272-7212 to schedule yours.
Our written price includes all labor, materials, permits, and project management from the first site visit through final inspection. That means architectural and structural drawings, San Francisco permit fees, seismic work where required, foundation, framing, roofing, electrical, plumbing, insulation, drywall, paint, flooring, fixtures, and the final sign-off. We also include a threshold for site cleanup. What it doesn't include is whatever the owner chooses to add beyond the original scope, and those additions get their own written price before we do them. You'll never see a surprise line item appear mid-job. Call (831) 272-7212 to get your project priced.
Service & Process FAQs
The San Francisco ADU permit process runs through the Department of Building Inspection and typically takes 4 to 8 months from application to approval. You'll need architectural drawings, a structural plan, and for garage conversions, a determination on parking replacement. San Francisco requires public noticing for some ADU types, which adds a month. Planning review happens first, then building review, then you pay fees and receive your permit. We handle the entire process on our projects, from drawing through approval, and we're familiar with what San Francisco reviewers look for. Call (831) 272-7212 and we'll help you understand where your project stands.
Once permits are in hand, construction on a typical San Francisco ADU takes 6 to 10 months. Detached units run toward the longer end, garage conversions toward the shorter. Permitting is the variable: 4 to 8 months is a realistic San Francisco timeline, and holidays and city staffing affect that. So from your first call to handing you the keys, plan on roughly 12 to 18 months for a detached ADU, and 10 to 14 months for a conversion. Weather here rarely stops work, but inspections scheduling can. We keep you updated at every step. Call (831) 272-7212 to discuss your timeline.
Yes, and garage conversions are one of the most common ADU types we build in San Francisco. The city has specific rules: the ground floor height matters, you may need to replace a covered parking space if you remove one, and the structure must meet current seismic standards. Most single-story garages with adequate ceiling height work well. We'll assess your garage, explain what San Francisco code requires for your specific situation, and give you a written price. Some garages in the Richmond and Sunset have unique foundation conditions, but we've handled plenty. Call (831) 272-7212 for a free assessment.
Yes. We pull every permit your San Francisco ADU requires, schedule all inspections, and stay on the job until the city signs off on the final. Permit drawings, structural calculations, Title 24 energy compliance, and all paperwork go through us. You won't spend afternoons at the Department of Building Inspection or track down a plan checker. We also walk the property with inspectors and handle any corrections they request. If a San Francisco inspector flags something, we fix it and get reinspection scheduled. That part of the job is ours. Call (831) 272-7212 if you want to know what permits your project needs.
Most San Francisco backyards can accommodate a detached ADU, but the city has setback rules, height limits, and lot coverage maximums that vary by zoning district. Rear yards must maintain a minimum setback, typically 4 feet from the rear property line. Height is generally capped at 16 feet for a detached ADU unless your lot allows more. We evaluate your specific lot, tell you what will fit and what won't, and work within San Francisco's ADU ordinance, which is among the most permissive in the state. Most lots we see can support a 400 to 800 square foot unit. Call (831) 272-7212 to find out what fits on yours.
Brands & Parts FAQs
We build custom ADUs and also work with prefab manufacturers where the site and budget favor it. In San Francisco, prefab from companies like Plant Prefab can work well for flat lots with clear crane access, though the city's narrow streets and overhead wires on blocks like the Outer Sunset sometimes complicate delivery. Boxabl's foldable units are compact and transportable, which suits tighter access. Prefab isn't always cheaper here because of foundation and utility work, but it can be faster. We'll help you decide whether prefab or site-built makes more sense on your lot. Call (831) 272-7212 to talk options.
We commonly use James Hardie fiber cement siding on San Francisco ADUs because it holds up to the fog, salt air, and wet winters better than wood or vinyl. It's rot-resistant, fire-rated, and comes in finishes that suit both modern and traditional San Francisco architecture. For the inner structure, we use standard dimensional lumber and engineered beams sized for seismic loads. Roofing is typically composition shingle or metal. We don't claim any material works for every house, and we'll show you samples and pricing before you commit. Call (831) 272-7212 and we'll walk you through your choices.
A detached ADU is a fully separate structure in your yard with its own foundations and four walls, while an attached ADU shares a wall with your main house and is built as an addition or conversion of existing space. In San Francisco, detached units typically offer more privacy for tenants and more design freedom for you, but they cost more because everything from foundation to roof is new. Attached units and garage conversions reuse existing structure, which lowers cost, but you'll live with closer proximity to whoever occupies the unit. Both rent for similar amounts in San Francisco. Call (831) 272-7212 to discuss which fits your lot and budget.
In most San Francisco cases, yes. The city sits on varying soil, from solid rock in some hill areas to sand and fill along former marshland, and the building code requires foundations engineered for those conditions. A new detached ADU needs a full foundation designed by a structural engineer and reviewed by the city. Garage conversions often need slab reinforcement or replacement, especially if the existing slab predates current seismic code. We include all foundation engineering in our written price, because skipping it in San Francisco isn't an option. Call (831) 272-7212 to find out what your specific site requires.
Licensing & Insurance FAQs
Every pro working under our name is required to hold the license and insurance their state requires, and that requirement is part of what Threshold Verified means. San Francisco also requires local business registration and compliance with city labor rules, which we follow. When you hire us, you get a written contract, a price locked before work begins, and a team vetted through the Threshold Standard: background-checked, identity-verified, and photo-badged. Nobody works on your San Francisco property who hasn't passed that bar. If you want to see credentials before we start, just ask. Call (831) 272-7212.
The difference is the Threshold Standard. Before our techs ever set foot on your San Francisco property, each one has been background-checked and identity-verified. You get the tech's name and photo before the visit. They arrive in a clean, marked uniform and show a photo ID badge at your door, every time. The price goes in writing before any work starts. That matters if you're a parent home with young kids or an older homeowner who feels uneasy opening the door to a stranger. We built this whole business around that worry. Call (831) 272-7212 and you'll see what we mean from the first call.
We're a local San Francisco branch of Sutton ADU Builders, which is the ADU company of the Threshold Group family. The brand has been building since 2006, and our San Francisco location is independently owned and operated, led by Miles Hartwell. That means we answer to this city, know its permit process, and work with local suppliers and crews. The standards and the guarantee behind us come from Sutton ADU Builders. The local knowledge and the hands on your project are here. It's the best of both: a national standard, delivered by neighbors. Call (831) 272-7212 to talk with our San Francisco team.
Our San Francisco location is led by Miles Hartwell, who runs the branch and oversees every project we take on in the city. Miles is the person responsible for what happens on your property. The parent company, Sutton ADU Builders, has been part of the Threshold Group family since 2006, and each location, including ours, is independently owned and operated. That structure keeps accountability local. When you call our San Francisco number, you reach our team, not a national switchboard. And when someone is scheduled to come to your home, you'll know their name and face before they arrive. Call (831) 272-7212.
Emergency & Response FAQs
If you see something concerning, like a new crack, a sagging beam, or water coming in where it shouldn't, the first step is to keep people away from the affected area and note what changed. Then call us at (831) 272-7212 during business hours, Monday through Friday 7:00 AM to 7:00 PM, or Sunday 7:00 AM to 7:00 PM. Describe what you're seeing and we'll help you decide whether it's urgent or can wait for a scheduled visit. Structural issues in San Francisco are worth taking seriously, particularly on hillside lots where soil movement is common. We'll get one of our local pros on it.
We're available Monday through Friday from 7:00 AM to 7:00 PM and Sunday from 7:00 AM to 7:00 PM. We're closed on Saturdays. During those hours you can reach our San Francisco team at (831) 272-7212 to schedule estimates, ask questions about an ongoing project, or talk through a concern. We don't claim to be a 24/7 operation, because we believe in telling you the truth about who we are and when you can reach us. Most project conversations happen during business hours anyway. Call us during our open hours and a live coordinator will connect you with the local team.
If you have a situation that can't wait, call us at (831) 272-7212 during our business hours, Monday through Friday 7:00 AM to 7:00 PM or Sunday 7:00 AM to 7:00 PM, and we'll assess the urgency with you on the phone. For truly dangerous conditions, like a gas smell or electrical arcing, call the utility or 911 first, then us. We'll help you triage what's happening and get a San Francisco pro scheduled as soon as our hours allow. We don't inflate expectations with "24/7 emergency service" language, but we do take urgent situations seriously. Call us and we'll figure out the right next step together.
Warranty & Guarantees FAQs
Every ADU we build is covered by Threshold Verified, which means the price is in writing before work starts and the people who show up are who we said they'd be. Every Threshold technician is background-checked, identity-verified, photo-badged, and sent to you by name and photo before the visit. If anyone arrives who you were not told to expect, that visit is on us and we make it right. Our workmanship is backed by a written warranty, and the specific terms for your project are spelled out in your contract before we begin. Call (831) 272-7212 and we'll show you exactly what's covered.
Threshold Verified is the standard that every Sutton ADU location works to, and it's the promise stamped on every job we do. It means every technician is background-checked and identity-verified. You get the tech's name and photo before the visit. They show a photo ID badge at the door, every time. They arrive in a clean, marked uniform. And the price goes in writing before any work starts. No exceptions. The name matters because a threshold is the entry point of your home, and who crosses it should never be a question. Call (831) 272-7212 to experience it.
Call us. Our workmanship is warrantied in writing, and if something we built fails under normal conditions during the coverage period, we make it right. San Francisco's climate and seismic activity put real stress on structures, and we'd rather hear from you early than let a small issue become a big one. We'll send a pro who's been background-checked and identity-verified, you'll know their name before they arrive, and they'll assess the situation honestly. If it's covered, we fix it. If it's wear and tear, we'll tell you that too and quote a fair repair. Call (831) 272-7212.
Still Have Questions?
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(831) 272-7212