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Get your free estimateGarage Conversion Contractor in San Bruno: Straight Answers on Cost, Zoning, and Feasibility
Most garage conversions in San Bruno run between $85,000 and $190,000 depending on whether you’re creating a bedroom, a full ADU with kitchen and bath, or something in between. The two factors that swing your price more than anything else are foundation work on San Bruno’s marine clay and the city’s architectural match review. We’re Lodgewick ADU San Francisco, part of the Kingswell family of home-service companies, and we’ve been handling Garage Conversion Contractor work across the Peninsula since 2010.
If you’re reading this from the Huntington neighborhood or off San Bruno Avenue, you already know the drill: small lots, older homes, and a city that actually looks at your plans. That’s not a bad thing. It just means you need a contractor who knows which questions to ask before you spend money on design. Call (707) 760-0502 and we’ll walk you through it.
What Makes a Garage Conversion Different in San Bruno
Here’s the thing most homeowners don’t learn until it’s too late: San Bruno isn’t like Millbrae or Daly City when it comes to ADU rules. The Mills Park and Crystal Springs neighborhoods carry a historic prohibition on new ADUs. That’s not a rumor, it’s in the zoning code. If you live there, a garage conversion is your only legal path to an attached rental unit, and a junior ADU is your only other option. Every other city on the Peninsula allows at least some new detached construction. San Bruno’s position is unique, and it changes how we approach every single project in those neighborhoods.
This is also why we tell every San Bruno homeowner the same thing before anything else: do the pre-application zoning check first. It costs a few hundred dollars and takes a couple weeks. Skipping it is how people end up with a full set of plans for a detached ADU that can never be permitted. We handle that check as part of our written estimate process so you’re never guessing.
Why San Bruno Homeowners Call Lodgewick ADU San Francisco
We’re not a franchise that parachutes in from out of town. Our crews serve San Bruno directly, coordinated from our San Francisco Bay Area office, and Russ Delmar leads our team on the ground. When you call (707) 760-0502, a live person answers, 24 hours a day, seven days a week. No voicemail tree, no chatbot, no “press 2 for billing.” You get a human who knows what a garage conversion in San Bruno involves.
Our reputation in San Bruno is built on something simple: we put the price in writing before any work starts. Not a ballpark, not a “we’ll see how it goes.” A written price. And we back every project with the 365-Day Done Right Promise, which is a written guarantee delivered before we ever swing a hammer. If the work isn’t right, we come back and make it right. That’s the Kingswell Guarantee, and it’s been the backbone of our company since 2010.
Homeowners in San Bruno have been burned before, and we know it. A price that changed at the door, a contractor who ghosted after the deposit, a finish that failed within months. We built Lodgewick to be the opposite of that, and the written guarantee is how we prove it.
Garage to Bedroom Conversion in San Bruno
A Garage to Bedroom Conversion in San Bruno typically costs $70,000 to $130,000, with most projects landing around $95,000. This is the right move when you need an extra bedroom for a growing family, aging parents, or a home office, but you don’t necessarily need a full second kitchen. The job involves converting the garage footprint into a conditioned living space with proper insulation, drywall, flooring, windows, and an egress point.
San Bruno’s older homes, mostly built from the 1940s through the 1970s, have garages that were never designed for living. That means the slab is often too thin, the walls lack insulation, and the electrical panel is usually maxed out. We scope all of that before we quote, so your written price already accounts for what’s hiding in the walls.
Bedroom Egress and Light Requirements
For a garage-to-bedroom conversion in San Bruno, the city requires an emergency escape and rescue opening, which usually means enlarging an existing window or cutting a new one. You’ll also need a minimum amount of natural light and ventilation, which typically means replacing the old garage door with a framed wall and windows that match your home’s existing style.
Foundation and Flooring Decisions
On San Bruno’s marine clay, we almost always recommend underpinning the existing garage slab before we build on it. The cost is real, usually $8,000 to $20,000 depending on the size, but skipping it is how you end up with cracked tile and a sagging floor five years later.
Garage Conversion ADU in San Bruno
A Garage Conversion ADU in San Bruno runs $120,000 to $220,000 as a full accessory dwelling unit with its own kitchen, bath, and entrance. This is the most common project we do in the city, especially in neighborhoods where detached ADUs aren’t allowed. You get a legal rental unit or in-law suite that generates income or houses family, all on the footprint you already own.
The interesting wrinkle in San Bruno is the two-story preference. On small 5,000 to 7,000 square foot lots, going up is often smarter than spreading out. If your garage has a good roofline and the existing structure can carry the load, a second story can double your living space without eating more yard. It costs more, but the per-square-foot number is often better than a single-story build-out.
Architectural Match Review
San Bruno requires ADUs to match the existing home’s architecture. That’s not a suggestion. It’s a condition of permit approval. We keep rooflines aligned, match exterior materials, and keep window patterns consistent. In practice, this means a 1950s ranch in Huntington gets a conversion that looks like it was always part of the house, not a box bolted onto the side.
Junior ADU Options in Mills Park and Crystal Springs
If you’re in Mills Park or Crystal Springs and your garage isn’t suitable for a full conversion, a junior ADU inside the existing home is still on the table. The cost is lower, typically $55,000 to $90,000, and the permitting path is simpler. We can walk you through both options so you know exactly what’s legal on your specific lot.
Trusted Brands We Service in San Bruno
We work with materials and systems we’d put in our own homes. That means James Hardie siding for San Bruno’s damp, foggy conditions, Plant Prefab for panelized wall systems when the timeline matters, and Tuff Shed as a starting point for detached structures where the lot allows. We keep common parts and materials in local supply for San Bruno jobs, which means fewer delays when the weather turns and the schedule shifts. If a product fails during the 365-day guarantee period, we come back and fix it, and we handle the warranty claim with the manufacturer ourselves.
Common Garage Conversion Contractor Problems We See in San Bruno Homes
Here’s what we actually find when we open up garages in San Bruno:
- Mills Park and Crystal Springs surprise. Homeowners buy a house, plan an ADU, and discover during permit intake that their address isn’t eligible. We catch this during the pre-application check, before any design money is spent, so you’re never stuck with plans you can’t use.
- Marine clay slab failures. San Bruno’s soil expands and shifts with moisture. A 3.5-inch unreinforced garage slab, common in homes built between 1940 and 1970, often heaves when new sewer lines are trenched through it. The fix is an underpinned foundation, and we scope it before quoting, not as a change order later.
- Wet-season drainage blowouts. On a 5,000 square foot lot, runoff has nowhere to go. Without re-sloping away from the converted garage, winter storms pond water against the new stem wall. We grade and drain as part of the build, and the final drainage inspection passes because we planned for San Bruno’s rainy months, not a dry October.
- Fog-driven moisture intrusion. Cool, damp air off the Pacific gets into everything. A garage conversion without proper vapor barriers and insulation develops musty smells and warped trim within two winters. We spec moisture-resistant drywall, seal the old sill against fog-driven soil dampness, and insulate to handle year-round cool conditions.
Pricing for Garage Conversion Contractor in San Bruno, CA
Here’s what we tell San Bruno homeowners on the first call, and it’s what goes in writing before any work begins. A garage to bedroom conversion runs $70,000 to $130,000. A full garage conversion ADU with kitchen and bath runs $120,000 to $220,000. A two-story ADU on top of an existing garage runs $180,000 to $260,000. A junior ADU inside the existing home runs $55,000 to $90,000.
What moves the number: foundation work on marine clay ($8,000 to $20,000), panel upgrades from 100 to 200 amps ($3,000 to $6,000), architectural match materials, and whether you’re going up or out. We give you a written line-item quote before you commit to anything. Call (707) 760-0502 and tell us your address, and we’ll give you a real number, not a range that changes when we show up.
We Also Serve Cities Near San Bruno
Our crews handle garage conversions throughout the northern Peninsula, including San Bruno, Millbrae, Daly City, San Francisco, and San Carlos. If you’re a few blocks outside city limits, chances are we’re already working nearby. The zoning rules change from city to city, but the way we work doesn’t: written price first, real arrival window, clean job site, and a guarantee in writing.
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 Garage Conversion Contractor in San Bruno
Yes, a garage conversion is generally your only legal path to an ADU in Mills Park or Crystal Springs, because San Bruno prohibits new detached ADUs in those two neighborhoods. Converting the existing attached garage preserves the existing footprint and avoids the prohibition. Junior ADUs inside the existing home are also allowed. Call (707) 760-0502 to have us run the pre-application zoning check on your specific property.
If your San Bruno lot is large enough for a detached garage, the conversion still goes through city building permits and San Mateo County environmental health review if you’re adding plumbing or altering drainage. The county looks at sewer connection adequacy and stormwater management. We handle the paperwork alongside the city permits so you’re not chasing approvals on your own.
San Bruno’s maritime fog means cool, damp air against your walls for much of the summer, so we spec closed-cell spray foam or rigid foam plus a proper vapor barrier to keep moisture out of the wall cavity. Skipping this step leads to mold and rot within a few years. Our moisture-resistant material choices are part of the written quote, not an add-on.
Many 1940s to 1970s garage slabs in San Bruno are unreinforced and only about 3.5 inches thick, which is too thin to carry the weight of finished living space or new plumbing trenches. The marine clay underneath expands with winter moisture and can heave the slab. We underpin the foundation before framing so your finished floors and walls don’t crack later, and we include that cost in your written price.
San Bruno’s architectural match requirement applies to second stories, meaning the upper floor’s roofline, materials, and window pattern must look consistent with the existing house. Setbacks also tighten on small lots, so we work within the existing garage footprint and cantilever where the code allows. We’ve done two-story conversions on 5,000 square foot lots, and the key is getting the city’s pre-application review early so the design meets their expectations on the first submittal.
Get Your Written San Bruno Garage Conversion Estimate
You don’t need to decide today. You need a real number and a straight answer about what’s possible on your specific San Bruno lot. Call (707) 760-0502 and ask for a garage conversion estimate. We’ll run the zoning check, scope the foundation, and hand you a written price before any work begins. The Kingswell Guarantee means the number on that paper is the number you pay, and if the work isn’t right within 365 days, we come back and make it right. That’s the whole deal.
Written by Russ Delmar, Owner at Lodgewick ADU San Francisco, serving San Bruno and the surrounding Peninsula communities since 2010.
