Fast, Reliable New Detached ADU Across San Bruno
A new detached ADU in San Bruno typically runs $285,000 to $420,000 all-in, from drawings through final inspection, with permit fees and utility connections included. That’s the honest range for a city where FAA Part 150 noise contours, postwar electrical panels, and a rental market fueled by SFO’s workforce all shape what gets built. Ellery ADU Studio has designed, permitted, and built detached units across San Bruno since 2015, and every project starts with a written price before any work begins. Call (971) 497-2402 to schedule a free site walk.
What makes San Bruno different from Millbrae or South San Francisco isn’t the lot sizes or the architecture. It’s the flight path. Approximately half the city sits inside FAA Part 150 noise contours tied to SFO’s primary departure and arrival corridors, which means a permitted detached ADU here has to clear sound-attenuation requirements that don’t even exist two miles north. We’ll get into exactly what that costs and how we handle it below. If you’re weighing a backyard unit on a rollover lot near Huntington Avenue or a hillside parcel up near Skyline, the math changes block by block. That’s the work we do.
Why Ellery ADU Studio Is San Bruno’s Preferred New Detached ADU Company
We’ve spent a decade opening up San Bruno homes built between 1946 and 1965, and the findings are predictable enough that we scope for them in writing before demo starts. Undersized 60A or 100A subpanels feeding the main house and the garage. Galvanized supply lines with a pencil-lead interior diameter. Cast-iron laterals that the city now requires replaced before an ADU permit can final. None of this surprises us anymore, and that’s the point. When our estimator walks a property off San Bruno Avenue or in the flatlands west of El Camino Real, they’re looking for exactly what the permit office will look for four months later.
We’re a design-build studio, not a contractor, which means the drawings, the permit set, and the construction live under one contract at one written price. The designer can’t blame the builder and the builder can’t blame the designer because they’re the same team. Under Haven Standard Clause 1, that price is on paper before you sign anything. No “call for a quote.” No door-side change orders on a surprise we could have caught during the walk.
Nadia Ellery founded the studio in 2015, the year California’s ADU permitting landscape shifted, and she’s built the practice around the permit set as the core product. That matters in San Bruno specifically because the city’s building department now reviews detached ADUs against FAA Part 150 noise contours, which means the drawings have to specify acoustic glazing, wall-mass calculations, and mechanical ventilation from the start. A generic ADU plan set filed here gets bounced. Ours don’t.
Our New Detached ADU Services in San Bruno
Custom Built ADU
A custom built ADU in San Bruno gives you full control over the footprint, roofline, and interior layout, which matters on the city’s tight 5,000 to 7,000 sq ft lots. We design around setback variances where the city allows them, and we build for the marine layer’s daily fog cycle. Custom units on western hillside parcels near the San Bruno Gap need a thermal envelope that a flat-lot unit in Daly City doesn’t. Our plans specify that from day one.
Prefab ADU Installation
We specify and coordinate prefab systems from Cover, Dvele, and Mighty Buildings for San Bruno homeowners who want a faster site assembly and a factory-controlled build. The prefab route works well on flat, airport-adjacent lots with clean crane access, and we handle the foundation, utility trenching, and permit set within the same single contract. One caveat we flag early: prefab wall assemblies often need supplemental acoustic mass to clear San Bruno’s sound-reduction checks. We add that into the written scope, not as a surprise later.
Modular ADU
Modular units from brands like Boxabl and Plant Prefab suit San Bruno parcels where the existing garage sits on a slab that was never permitted for a second dwelling. We scope the foundation separately, coordinate the module delivery through streets where overhead clearances get tight, and tie the new unit into a separate meter so you don’t trip the main house when both HVAC systems run. That separate-meter conversation happens at the estimate, not after the city rejects the load calc.
Studio ADU
A studio ADU in San Bruno runs about $195,000 to $260,000, and it’s the most common starting point for homeowners who bought at a high price and want a rental asset without overbuilding. The SFO rental pool rewards studios disproportionately: a 400 sq ft unit within 15 minutes of the terminals rents to ramp agents, ground crew, and rotating flight staff who don’t need a second bedroom. We design studios with sealed mechanical ventilation and acoustic glazing so the noise package works, not just passes inspection.
1-Bed & 2-Bed ADU
A 1-bed or 2-bed detached ADU in San Bruno typically runs $320,000 to $420,000, and the gap between those numbers comes down to foundation condition, panel capacity, and how much noise mitigation the parcel’s location requires. Homes in the flatlands near Tanforan or along Huntington Avenue often already carry window upgrades from SFO’s Community Noise Insulation Program on the main house. The new ADU doesn’t. We price the ADU’s own noise package separately and show it on the written estimate as its own line item, because it is its own line item.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in San Bruno
We specify and coordinate prefab and modular systems from Cover, Dvele, and Mighty Buildings across San Bruno, and we stock the acoustic underlayment, dual-pane glazing units, and ERV components these installations need when they’re going in under a flight path. Because we buy these materials for a specific San Bruno parcel’s noise contour rather than a generic Peninsula spec, lead times stay shorter and the permit review doesn’t stall on a missing acoustic test report. When a modular unit from Boxabl lands on a lot off Sneath Lane, our crew handles the setup, the utility tie-in, and the final sound-reduction verification the city requires.
Common New Detached ADU Problems We See in San Bruno Homes
- Single-pane windows that pass plan review and fail field inspection. The city measures interior sound levels during a passing A320 takeoff, and a unit with builder-grade glazing reads 45+ dBA inside. We specify dual-pane acoustic windows with the correct STC rating from the first drawing, so the field test clears the first time.
- A 60A or 100A panel already maxed out by the main house. Tying a new detached ADU into an original postwar subpanel causes breakers to trip the moment both HVAC systems cycle on. The city won’t final until a separate meter or an approved load calc is submitted. We scoped one panel upgrade on Huntington Avenue where the subpanel was feeding both the house and the detached garage, and it was on the written estimate before demolition started.
- A tight, quiet envelope with no mechanical ventilation. The fog that pours through the San Bruno Gap turns a well-sealed ADU into a humidity box, with condensation collecting on the double-pane glass within the first winter. We include an ERV or comparable sealed ventilation system in every San Bruno unit, because operable windows defeat the noise package the FAA inspection is checking for.
- Galvanized supply lines down to a pencil-lead interior. Homes built between the late 1940s and 1960s in the neighborhoods west of El Camino Real frequently carry original galvanized plumbing that the permit office flags when the ADU ties in. We replace the lateral before the ADU permit can final and show that cost in the written scope, not as a door-side surprise.
Pricing for New Detached ADU in San Bruno, CA
Here are the ranges we quote across San Bruno, and these numbers include drawings, permits, utility connections, and the noise mitigation package the parcel requires:
- Studio ADU: $195,000-$260,000
- 1-Bed ADU: $285,000-$350,000
- 2-Bed ADU: $340,000-$420,000
- Prefab or modular unit (site work included): $250,000-$390,000, depending on module spec and acoustic upgrades
- Panel upgrade and lateral replacement (when triggered by permit review): $8,000-$18,000, scoped and priced before you sign
Two things move the price more than anything else in San Bruno. First, the parcel’s location relative to FAA Part 150 noise contours. A unit on a flat lot off Huntington Avenue may need a standard acoustic package, while a unit up near Skyline under the heaviest departure corridor may need triple-pane glazing, added wall mass, and a sealed ventilation system that wasn’t on the original wish list. Second, what’s behind the walls of the existing house. If the subpanel is 60A and the laterals are galvanized, the city will require upgrades before the ADU final. We write those into the contract as allowances so the price doesn’t move after demo. Call (971) 497-2402 for a free site walk and a written price before any work starts.
We Also Serve Cities Near San Bruno
Our crews serve San Bruno and the surrounding Peninsula cities, including South San Francisco, Pacifica, Daly City, and Burlingame. Each city has its own permit quirks, and we carry the documentation to file in all of them. If you’re considering a New Detached ADU anywhere in the corridor, the same one-contract design-build model applies. You can see how our work in San Bruno handles the flight-path challenge specifically.
Serving San Bruno, CA - Our Local Coverage Area
We’re based in the San Bruno 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 - New Detached ADU in San Bruno
No, and that’s the trap. SFO’s Community Noise Insulation Program covers only the primary dwelling on a parcel, not any detached unit built later. A new ADU in San Bruno gets its own acoustic requirements through the city’s permit review and FAA Part 150 noise contour compliance, which means dual-pane acoustic glazing, additional wall mass where the parcel’s noise exposure demands it, and sealed mechanical ventilation. We’ve had homeowners assume the main house’s upgraded windows extended to the backyard unit, only to fail the field inspection on the ADU’s interior sound levels. Call (971) 497-2402 and we’ll check your parcel against the current noise contour map before the first drawing is filed.
The two most common are a panel upgrade and a lateral replacement. A 1950s ranch on a 5,000 sq ft lot typically carries a 60A or 100A subpanel, and tying a new dwelling into that panel triggers a load calc that rarely passes. The city will require a separate meter or a panel upgrade before the permit can final. The lateral is the other one: galvanized supply lines from that era are often reduced to a fraction of their original interior diameter, and the plumbing inspector will flag the tie-in. On a flat lot off Huntington Avenue, our crew found a 60A subpanel feeding both the main house and the detached garage, plus galvanized lines that were down to a pencil-lead interior. We scoped both upgrades into the written estimate before demolition started. Call (971) 497-2402 and we’ll tell you what your specific house will trigger during the site walk.
Because operable windows defeat the noise package the FAA inspection exists to verify, and the San Bruno Gap’s daily fog makes a tight, window-sealed unit into a humidity problem. The cold marine layer that pushes through the gap condenses on double-pane glass within weeks, and the mold risk is real. A sealed ERV or comparable ventilation system exchanges air without opening the envelope, so the unit stays quiet under the 3 p.m. departure wave and stays dry through the fog season. We include this as a line item in every San Bruno ADU scope, not as an add-on at final. For an exact number on your parcel, call (971) 497-2402.
We price the panel replacement into the written scope before you sign anything, and we submit the load calc with the permit set so the city doesn’t pause the review. A 60A panel from the 1950s cannot legally serve a new dwelling while also feeding the main house, and the city won’t final the ADU permit until a separate meter or an upgraded panel with an approved load calc is on file. This is a known cost in San Bruno. It’s not a surprise. On the Huntington Avenue project, the panel upgrade and lateral replacement were in the contract at signing, and the client saw the line items before demo began. Call (971) 497-2402 and we’ll scope your panel during the free site walk.
Yes, and it’s one of the densest rental pools on the Peninsula. SFO employs roughly 50,000 people on-site, plus rotating airline crews and ground staff who don’t need a long lease. A studio or 1-bed ADU within 15 minutes of the terminals rents quickly to ramp agents, mechanics, and flight attendants who want a quiet place to sleep between shifts. That’s also why the noise package isn’t a compliance expense; it’s the reason the unit rents at all. A sound-attenuated unit near SFO commands a premium over a comparable unit in Daly City that just happens to be quiet because it’s outside the contour. Call (971) 497-2402 and we’ll walk you through what your specific parcel will rent for after the noise math is done.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving San Bruno since 2015.