Frequently Asked Questions

Most ADU projects in San Francisco take 9 to 14 months from design to final inspection. The timeline breaks down roughly like this: design and drawings take 4 to 8 weeks, San Francisco permitting adds another 2 to 6 months depending on project complexity, and construction itself usually runs 4 to 7 months for a garage conversion or 6 to 9 months for a detached unit. Homes in historic districts or on steep lots in neighborhoods like Twin Peaks may face longer city review. We give you a written schedule before starting, and we text photo updates throughout construction so you always know where things stand. Call (424) 328-5746 to get a timeline estimate for your property.

The first step is a site visit and a written feasibility estimate. We walk your lot, check zoning setbacks, review your existing utility connections, and tell you honestly what's possible and what it'll cost. San Francisco has specific ADU rules around lot coverage, rear yard setbacks, and height limits that vary by neighborhood, and the zoning differences between, say, the Outer Sunset and the Mission can change your design significantly. After the site visit, we provide a written line-item price before any design work begins. Taking this step early saves you months of planning down the wrong path. Call (424) 328-5746 to book your free site visit.

Yes, hillside ADUs are entirely possible in San Francisco, though they require more structural engineering and a higher budget. Sloped lots in areas like Diamond Heights, Miraloma Park, or the slopes above Castro demand retaining walls, deeper foundations, and sometimes caissons drilled into bedrock. San Francisco's geological hazards, including the city's proximity to active faults, mean the engineering on hillside projects must be especially rigorous. We've built on slopes where the grade change exceeds 20 feet, and we'll tell you honestly what your specific hillside requires before you commit. Call (424) 328-5746 and Troy will assess your lot firsthand.

We manage the design process end-to-end with architects and drafters who know San Francisco's ADU ordinance inside and out. You won't have to interview multiple design firms or decode city submittal requirements yourself. The design phase includes site measurement, floor plan development, elevation drawings, and all documentation the San Francisco Planning Department and Department of Building Inspection require. We also work with modular and prefab makers like Boxabl when the lot suits it, which can compress design time significantly. Your written price includes design fees, so there are no surprise architect invoices. Call (424) 328-5746 to discuss what's possible on your lot.

We serve the entire city of San Francisco, from the Outer Richmond to the Bayview and everywhere between. Our local team regularly works in the Sunset, the Mission, Noe Valley, Bernal Heights, Potrero Hill, Excelsior, Visitacion Valley, and the Portola, among many other neighborhoods. We also take ADU projects just south of the city in Daly City and Brisbane, where many San Francisco homeowners own rental property. If you're not sure whether we cover your exact street, call (424) 328-5746 and ask, but the short answer is yes, we cover all of San Francisco.

Yes, we install and finish prefab ADUs from manufacturers including Boxabl, Plant Prefab, and Tuff Shed when the project calls for it. Prefab can work well on San Francisco lots with easy crane or forklift access, particularly in flatter neighborhoods like the Outer Sunset or Bayview. On tight hillside lots, a traditional stick-built or panelized approach usually fits better. We'll evaluate your site and tell you which path makes sense. Prefab often shortens on-site construction time by several months, though the price difference versus stick-built isn't always as large as homeowners expect. Call (424) 328-5746 to compare prefab and traditional options for your lot.

We recommend fiber cement siding from James Hardie for most San Francisco ADUs because it handles the city's fog, salt air, and damp winters better than wood or vinyl. Many of our projects in the Sunset and Richmond, where ocean moisture is constant, use Hardie plank or panel for the exterior cladding. For a modern look, some homeowners pair fiber cement with metal accents or smooth stucco. The key is choosing materials that handle San Francisco's microclimate: wet, salty air near the coast and steep temperature swings inland. We'll spec materials that last and look right in your neighborhood. Call (424) 328-5746 to talk materials.

Almost every ADU in San Francisco requires a concrete foundation designed for the city's specific seismic and soil conditions. In most neighborhoods, that means a standard poured concrete perimeter foundation with rebar. In liquefaction zones, which cover much of the city's eastern waterfront, including the Mission Bay and South Beach areas, the foundation may need to be deeper and more heavily reinforced. In hillside areas, you're often looking at pier-and-grade-beam systems or retaining structures. We have geotechnical engineers assess the soil and seismic risk on every project before foundation work begins. Call (424) 328-5746 and we'll walk you through what your specific lot requires.

Our company operates with the proper licensing and insurance required for general contracting work in California, and every pro working under our name is required to hold the license and insurance their trade requires. Benson ADU San Francisco carries liability coverage for the work we perform, and we're glad to provide documentation of our coverage before you sign anything. The city of San Francisco requires licensed contractors for all ADU construction, and we meet every requirement. When you work with us, permits are pulled in the proper name and every inspection is scheduled with the Department of Building Inspection. Call (424) 328-5746 and we'll send over our credentials.

Yes, we pull every permit an ADU project in San Francisco requires. That includes the planning application through the San Francisco Planning Department, the building permit through the Department of Building Inspection, and any additional approvals from the SFPUC, PG&E, or the Fire Department. You won't be chasing paperwork or sitting on hold with city departments. We handle the submittals, the corrections, and the resubmissions. That's part of why our written estimates include permit fee line items: you see exactly what the city charges and exactly what we're doing on your behalf. Call (424) 328-5746 to get your permit process started.

Inspection failures are rare when work is done correctly the first time, which is why we schedule third-party checks before city inspections. If an inspector does flag something, we correct it at no additional cost to you and reschedule the inspection. That's not a policy we write in fine print; it's simply how we work. San Francisco inspectors are thorough, particularly around seismic anchoring, electrical, and egress requirements, so we build to code from day one rather than patching after the fact. You always get photo updates of the work so you can see what the inspector sees. Call (424) 328-5746 and ask Troy what a typical inspection cycle looks like.

Call us directly at (424) 328-5746 and someone will respond. Our phone hours are Monday through Friday from 7:00 AM to 7:00 PM, and Sunday from 7:00 AM to 7:00 PM. If something happens during construction hours, whether it's a water line break or an unexpected structural discovery, we'll be on the phone with you quickly and on-site as soon as the situation warrants. For anything involving gas lines, active electrical hazards, or flooding, we coordinate with the proper utility companies and city departments so the issue is handled safely and correctly. We never leave a problem unaddressed overnight when it affects your safety.

Our phone lines are open Sunday from 7:00 AM to 7:00 PM, and closed Saturday. Monday through Friday, we answer from 7:00 AM to 7:00 PM. You can always leave a message outside those hours and we'll return your call first thing when we're back. For current clients with active projects, we provide a direct line to your project lead so you're not starting from scratch every time you call. Most questions about scheduling, materials, or inspections can be answered during our regular hours, and we'll make sure you're never left wondering. Call (424) 328-5746 during business hours and we'll take care of you.

If a roof we installed leaks, that's a workmanship issue, and it's covered under our workmanship warranty, which we honor for the agreed period spelled out in your written contract. We don't give vague promises; the warranty terms are in writing before you sign anything, and they cover both labor and the integrity of our installation. Material warranties from manufacturers like James Hardie add another layer of protection on top of our workmanship coverage. If water is actively coming into your ADU during a San Francisco winter storm, call (424) 328-5746 and we'll get someone out to assess the situation.

Every ADU we build is covered by a written workmanship warranty, and the exact terms, including the duration, are spelled out in your contract before construction starts. We put the price in writing before we start, and we put the warranty in writing too. Manufacturer warranties on materials like James Hardie siding, roofing systems, windows, and appliances run alongside our workmanship coverage, and we help you register every product warranty after final inspection. If something we installed fails due to our workmanship within the warranty period, we fix it. Call (424) 328-5746 and we'll walk you through exactly what our warranty covers on your project.

The Relay Visibility Guarantee is the promise every Benson ADU location works to: total visibility on every job. You get a live arrival time you can track to your door, photo updates of the work before and after, and a written price before anything starts. That means you always know who is coming, when they will be there, and what it will cost. The guarantee is backed by The Relay Standard, the code every Relay Home Co. partner follows: book in a tap with no phone tag, get a live arrival time instead of a four-hour window, see photos of the work, receive the price in writing before work starts, and pay from a digital invoice link sent to your phone. Call (424) 328-5746 to experience how it works.

We don't hide behind vague "satisfaction" language. What we offer is specific: a written price before work begins, photo documentation of every phase, a live arrival time for every scheduled visit, and a workmanship warranty with terms in writing. If something isn't right, we make it right, and the process for raising a concern is simple: call us and talk to a real person. The Relay Standard, our parent company's operating code, requires exactly this level of accountability from every independent location. That's the guarantee, and it's not marketing language. It's how we run every San Francisco ADU project. Call (424) 328-5746 to get started.

San Francisco allows ADUs on almost every residentially zoned lot, regardless of size. State law, specifically the ADU statutes that went into effect in 2020 and were expanded in 2023, requires cities to approve ADUs up to 800 square feet or one bedroom regardless of lot size. On a small lot in neighborhoods like the Inner Richmond or the Mission, you may be limited to a junior ADU or a compact one-bedroom unit, but the legal path exists. We'll assess your specific lot, check the zoning, and tell you exactly what square footage you're entitled to build. Call (424) 328-5746 and we'll start that assessment.

San Francisco's ADU ordinance, which incorporates state mandates, controls height limits, rear yard setbacks, lot coverage limits, and parking requirements. Most ADUs in San Francisco are exempt from additional parking requirements if they're within a half mile of transit, which covers most of the city. Height limits for detached ADUs are typically 16 feet, though attached ADUs can often match the primary structure's height. Rear yard coverage rules vary by zoning district, with RH-1 and RH-2 zones having different allowances than RH-3 and mixed-use zones. We handle every zoning compliance detail. Call (424) 328-5746 with your address and we'll tell you what applies.

Yes, building an ADU in San Francisco increases your property taxes because the county assessor reassess the property based on the added value of the new structure. However, the reassessment applies only to the ADU's added value, not the entire property. So if your home is currently assessed at $800,000 and the ADU adds $350,000 in value, you'll pay taxes on the $350,000 portion at the standard rate. Some San Francisco homeowners explore exemptions, like the homeowner's exemption or the senior citizen exemption if they qualify. It's worth a conversation with a tax professional, and we're happy to share the construction value figures they'll need. Call (424) 328-5746 for your written project valuation.