A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in San Jose, CA
Fielding ADU San Jose builds accessory dwelling units, garage conversions, and room additions across San Jose. Most of the homes we work on are single-family ranch and tract houses from the 1950s through the 1970s, with generous backyards and detached garages that make ADU construction practical. San Jose’s Mediterranean climate and the city’s push to densify older neighborhoods shape how we approach every job. Call (669) 201-3984 to talk through your lot and budget.
Why San Jose Homes Are Different
San Jose’s housing stock creates a specific set of conditions for ADU work. The majority of homes we walk are single-story ranch layouts built between 1950 and 1975, with expansive rear yards and detached garages set back from the main house. Those big lots are exactly why the city has become a hub for backyard ADUs. But the age of these homes means we regularly find 100-amp electrical panels that need upgrading before an ADU can be connected, and cast-iron drain lines that require replacement to pass inspection.
The local geography matters too. San Jose sits on flat valley floor in most neighborhoods, but areas like the East Foothills and Almaden Valley have sloped lots that affect drainage design and foundation work. Winter rains arrive in concentrated bursts between December and February, so rainwater runoff management is part of every site plan we prepare. Willow Glen has its own pattern: many homeowners are converting detached garages accessed by alleys into ADUs, which creates a secondary frontage facing the alley rather than the street. That changes how we think about entry, address, and utility hookups on those jobs.
Permit realities are different here as well. San Jose’s planning department processes ADU applications under California state law that overrides many local restrictions, but the city still enforces setback requirements, height limits, and fire-safety standards. We handle the paperwork and inspections as part of every project.
Our Main San Jose Services
San Jose homeowners call us most often about three types of projects: adding square footage to the main house, converting an existing garage into living space, and building a new backyard ADU. Each has its own page with pricing, process, and San Jose-specific detail.
Room Addition Contractor in San Jose
Room additions in San Jose often mean expanding a 1950s ranch home that was built smaller than today’s households need. We handle foundation matching, roofline integration, and electrical panel upgrades on these jobs. Because many of these homes sit on large lots, a ground-floor addition is usually the most economical path rather than going up. The flat terrain in most of San Jose keeps foundation costs predictable. For the full breakdown, see our Room Addition Contractor in San Jose page.
Garage Conversion Contractor in San Jose
Detached garages from the post-war era are common across San Jose, and converting one is typically the fastest way to add a rental unit or in-law suite. On these jobs we replace the slab if needed, insulate and drywall, run new electrical, and add a kitchenette and bath. In Willow Glen, alley-loaded garages convert into units that feel like their own small home. The main variable we check is the existing foundation, because older garage slabs were rarely poured to living-space standards. Details are on our Garage Conversion Contractor in San Jose page.
ADU Builders in San Jose
Backyard ADUs are the primary strategy San Jose homeowners use to add rental income or housing for aging parents. We build conventional stick-frame ADUs with James Hardie siding and work with prefab platforms like Abodu and Cover when the site and budget support it. San Jose’s large lots mean most ADUs are detached, which keeps construction off the main house and avoids the noise of working inside your home. Every ADU we build is permitted and inspected. Read the full scope on our ADU Builders in San Jose page.
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 Jose
We work with Tuff Shed structures for certain garage and studio conversions, James Hardie siding on conventional builds, and prefab platforms including Abodu and Cover when a factory-built unit fits the lot and timeline better. See our brands page for more on which approach suits which site.
Pricing for ADU Company in San Jose, CA
| Service | Typical range in San Jose |
|---|---|
| Detached ADU (1 bed / 1 bath, ~500 sq ft) | $180,000 – $260,000 |
| Detached ADU (2 bed / 1 bath, ~700 sq ft) | $230,000 – $320,000 |
| Garage conversion to ADU (attached garage) | $90,000 – $150,000 |
| Garage conversion to ADU (detached garage) | $110,000 – $170,000 |
| Room addition (ground floor, 300 – 500 sq ft) | $130,000 – $210,000 |
| Room addition (second story, 300 – 500 sq ft) | $190,000 – $290,000 |
| Electrical panel upgrade (100A to 200A) | $3,500 – $6,000 |
| Foundation repair or slab pour for ADU | $12,000 – $28,000 |
| Tuff Shed finish-out as studio | $35,000 – $70,000 |
What pushes the number up in San Jose is usually site-specific: panel upgrades on older homes, sewer line replacement when a garage conversion requires it, or sloped-lot foundation work in the East Foothills. Every price goes in writing before work starts, and that written number is what you pay at the end.
Neighborhoods We Serve in San Jose
We work across the full city of San Jose, from the valley floor to the foothill edges. Our crews are local to the South Bay and typically reach most San Jose neighborhoods within a day for site visits.
- Willow Glen
- Almaden Valley
- Rose Garden
- East Foothills
- Cambrian
Service Area – Cities Near San Jose
Fielding ADU San Jose serves homeowners across Santa Clara County. In addition to San Jose proper, we regularly work on projects in Santa Clara, CA, Sunnyvale, CA, Campbell, CA, and Saratoga, CA.
Serving San Jose, CA - Our Local Coverage Area
We’re based in the San Jose 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 Jose
Once plans are approved, we typically break ground within four to eight weeks, depending on permit turnaround and your site’s readiness. Prefab platforms like Abodu can shorten that timeline. Call (669) 201-3984 to get a realistic start date for your lot.
No. The state of California removed owner-occupancy requirements for ADUs, and San Jose follows state law. You can rent both the main house and the ADU. We verify current rules on every project before you commit.
Yes. Every project we build is permitted through the City of San Jose and inspected at each required stage. The written price you approve includes permit handling and inspection coordination. Call (669) 201-3984 for a free estimate, and we’ll walk through the permit path for your specific property.
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 Jose Customers Say
"Insulation, drywall, and finishes were all well done. Feels like part of the house."
- Pete O."Garage conversion with a new bath and kitchenette. Permit was handled by them. Inspection passed first time."
- Sheila B."Honest feedback on what the lot could fit. Told me up front what would fit on the lot and what the setbacks would allow."
- Rita C.
