A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in San Bruno, CA
Most San Bruno homeowners call us because they’ve outgrown their house but not their neighborhood. The lots here run small, usually 5,000 to 7,000 square feet, which means adding square footage takes real planning, not just a bigger footprint. Fog, damp winters, and homes built between the 1940s and 1970s all shape how an ADU, garage conversion, or home addition needs to be designed and built. If you’re weighing your options, an accessory dwelling unit (ADU, a separate small home on your existing lot) is often the smartest way to add space without moving. Call (707) 760-0502 and we’ll walk you through what’s realistic for your property.
Why San Bruno Homes Are Different
San Bruno’s housing stock tells a clear story: most homes were built from the 1940s through the 1970s, a mix of ranch-style and two-story designs on modest lots. What that means for construction is predictable but important. Original foundations often need assessment before we add weight or square footage. Electrical panels from the 1960s frequently need upgrading before a new dwelling unit can be permitted. None of this is unusual for us, but it’s exactly the kind of thing that separates a real San Bruno ADU specialist from a contractor who mostly builds in newer subdivisions.
The climate adds another layer. San Bruno sits right where Bay fog rolls over the peninsula, so summers stay cool and damp while winters bring steady moisture. We specify moisture-resistant materials and proper insulation on every project because a poorly sealed ADU here will show problems within a few seasons. And because outdoor living space isn’t usable year-round the way it is inland, homeowners tend to prioritize interior square footage over patios and decks.
The single biggest San Bruno-specific factor, though, is zoning. The Mills Park and Crystal Springs neighborhoods carry a historic prohibition on new detached ADUs. Homeowners there can still pursue garage conversions or junior ADUs, but a freestanding unit in the backyard is off the table. Elsewhere in San Bruno, detached ADUs are allowed but must match the existing home’s architecture, which pushes many families toward two-story ADU designs to get usable space on a small footprint. Russ Delmar and our team work through these rules before any drawings start, because the wrong assumption at the beginning costs months and money later.
Our Main San Bruno Services
San Bruno homeowners usually come to us with one of three goals: add a room or wing onto the existing house, convert a garage into living space, or build a detached ADU in the backyard. Each path has its own permit realities and cost structure, and each one has a dedicated San Bruno page with full details.
Home Addition Contractor in San Bruno
A home addition in San Bruno works best when it respects the original house. On lots where setbacks leave little room to spread outward, a second-story addition often makes more sense than extending the ground floor, and that brings foundation and structural questions we address early. San Bruno’s damp climate also means tie-ins between old and new framing need careful flashing and sealing to prevent moisture intrusion at the junction. For a full breakdown of how we approach additions here, see Home Addition Contractor in San Bruno.
Garage Conversion Contractor in San Bruno
For homeowners in Mills Park and Crystal Springs, a garage conversion (turning an attached or detached garage into a habitable room or ADU, often called a JADU when it’s attached and under 500 square feet) is frequently the only path to new living space without moving. The original slab, the existing roofline, and the electrical service all determine what’s feasible, and San Bruno’s permit office reviews these conversions carefully. You can read about what a garage conversion typically involves and costs in San Bruno on Garage Conversion Contractor in San Bruno.
ADU Builders in San Bruno
A detached ADU (accessory dwelling unit, a separate small house on your lot) gives San Bruno homeowners a rental unit, a place for aging parents, or a quiet home office. The city requires the ADU to match the existing home’s architecture, which shapes everything from rooflines to siding choices, and two-story designs are common because they preserve yard space on small lots. We work with owners in eligible San Bruno neighborhoods through the full process. See ADU Builders in San Bruno for detail on ADU-specific costs and timelines.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Brands We Service in San Bruno
We install and service units from Abodu, Tuff Shed, and Plant Prefab, and we use James Hardie siding on many San Bruno builds because it holds up to the damp, cool climate better than most alternatives. Parts for common systems are stocked through our Bay Area supply chain, which keeps turnaround times shorter than most San Bruno homeowners expect. See our brands for what we carry and why we chose them.
Pricing for ADU Company in San Bruno, CA
These are typical ranges for the San Bruno market. They are ballpark figures, not a quote; your written estimate comes after we look at your lot, your existing structure, and your permit path.
| Service | Typical range in San Bruno |
|---|---|
| Detached ADU, new build | $250,000 – $450,000 |
| Garage conversion to ADU | $120,000 – $220,000 |
| Attached JADU | $100,000 – $180,000 |
| Home addition (single room) | $80,000 – $150,000 |
| Second-story addition | $200,000 – $400,000 |
| Electrical panel upgrade (required on many San Bruno homes) | $3,500 – $7,000 |
| Foundation repair or reinforcement before ADU build | $8,000 – $30,000 |
| Architectural and engineering plans | $8,000 – $20,000 |
| Site preparation and utility connections | $10,000 – $25,000 |
What pushes a San Bruno price toward the top of a range is usually an old foundation, an undersized electrical panel, or a lot with tight setbacks that forces a more expensive two-story design. Whatever the number is, you’ll see it in writing before we start, and the price we write is the price you pay.
Neighborhoods We Serve in San Bruno
Our crews work across the city, including several neighborhoods where ADU and addition rules differ meaningfully:
- Mills Park
- Crystal Springs
- Rollingwood
- Portola Highlands
- Lomita Park
Most San Bruno estimates are scheduled within a few business days, and our scheduling team can usually accommodate evening walk-throughs for homeowners who work in the city.
Service Area – Cities Near San Bruno
We also take on ADU, garage conversion, and home addition projects in neighboring communities on the peninsula and up the coast. You’ll find the same written-price commitment and the same 365-Day Done Right Promise in Millbrae, CA, Daly City, CA, San Francisco, CA, and San Carlos, CA.
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 About ADU Company in San Bruno
Plan on four to eight weeks from signed agreement to permit submittal, depending on whether your property needs upgraded electrical service or foundation work first. San Bruno’s plan review times vary by project type, and we’ll give you a realistic schedule once we’ve seen your lot. Call (707) 760-0502 for a free estimate and timeline.
Mills Park and Crystal Springs currently prohibit new detached ADUs, which means attached units like JADUs and garage conversions are the permitted path for adding living space there. Elsewhere in San Bruno, detached ADUs are allowed when they match the existing home’s architecture. We verify your specific lot’s status before any planning begins.
In many cases, yes. Homes built in the 1940s through 1970s often carry 100-amp or smaller panels and original foundations that need evaluation before a permitted ADU or addition can be approved. We include these assessments in our site visit so your written estimate covers the real scope, not a surprise later. Call (707) 760-0502 to schedule your free estimate.
What happens when you call
- 1A real person answersNo phone trees - talk to a local adu pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3We come out and measureLicensed & insured, at a time that suits you - the visit and the quote are both free.
- 4You get the price in writingLine-itemed, yours to keep, and nothing starts until you say go.
What San Bruno Customers Say
"The ADU came out beautiful and the permitting, which terrified me, was handled start to finish. They kept me updated every week so I was never wondering what was happening."
- Shauna Mills"Turned our detached garage into a little guest house. Clean crew, respectful of the neighbors, and no mystery charges at the end. Love how it turned out."
- Carmela Fontes"I was nervous about adding on but they walked me through every step and every cost before we started. No surprise change orders halfway through like I'd heard horror stories about."
- Eleanor Pratt
