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
Adding an ADU or home addition in San Jose means building on some of the most valuable residential lots in California, where housing demand has outpaced supply for decades. The city’s mix of older bungalows, mid-century ranch homes, and tightly regulated tear-down lots means every project starts with a careful look at setbacks, lot coverage, and seismic requirements. We’re Sutton ADU San Jose, and our job is to give you a written price, a vetted crew you know by name and face, and a one-year promise on the work. Call (669) 444-4530 to start with a free estimate.
Why San Jose Homes Are Different
San Jose’s housing stock splits into two broad categories that shape ADU projects in very different ways. The older neighborhoods, places like Naglee Park and the Rose Garden, are full of early-20th-century bungalows on compact lots with shallow setbacks and mature trees that influence where a detached unit can legally sit. The post-war expansion, especially across the western and southern stretches of the city, produced thousands of mid-century ranch homes on larger lots, often 6,000 square feet or more, which are far friendlier to detached ADUs and room additions.
The bigger constraint in San Jose is the seismic standard. Because the city sits near the Hayward and Calaveras fault systems, every structure, including a 500-square-foot backyard unit, must be engineered for lateral force resistance. That affects foundation depth, shear wall placement, and connection details between an addition and the existing home. It also affects cost, which is why our written estimate accounts for structural engineering from the first draft, not as a surprise line item after plans are drawn.
San Jose also applies its own ADU rules on top of state law. Minimum lot sizes, owner-occupancy requirements in some zones, and local fire-access standards can change whether a detached unit is straightforward or needs discretionary review. We walk every San Jose client through those specifics before you commit to plans, because the lot you own determines the ADU you can build.
Our Main San Jose Services
Most San Jose homeowners reach out to us for one of three projects: a full home addition, a detached or attached ADU, or a single-room extension. Each has its own San Jose page with pricing and details.
Home Addition Contractor in San Jose
A home addition in San Jose usually means expanding a ranch home’s footprint, often into a side or rear yard that has been underused for years. The work includes foundation matching, seismic tie-ins to the existing structure, and roof integration that keeps the original lines intact. In San Jose’s post-war neighborhoods, we regularly work with lots large enough for a 400 to 800 square foot addition without tripping lot-coverage limits. Get the full picture on our Home Addition Contractor in San Jose page.
ADU Builders in San Jose
San Jose homeowners build ADUs for two reasons: keeping family close or generating rental income in a market where even a modest unit rents quickly. Detached ADUs in the 400 to 800 square foot range are the most common request, and San Jose’s larger mid-century lots often accommodate them without sacrificing the main home’s yard. We handle site prep, foundation, utility trenching, and finish work, and we also work with prefab lines where a factory-built shell makes sense for the lot. Details are on our ADU Builders in San Jose page.
Room Addition Contractor in San Jose
A room addition is the most surgical way to add space in San Jose’s older bungalow neighborhoods, where a full second story isn’t always practical. We frame and finish single-room extensions, typically for a bedroom, home office, or expanded kitchen, and we handle the structural connection to the existing foundation, which matters in a seismic region. Because San Jose lots in older districts are tighter, we often work within 3 to 5 feet of a property line, which requires careful setback planning. See specifics on our Room Addition Contractor 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 Abodu, Cover, and James Hardie exterior systems, plus Tuff Shed structures when a conversion makes sense. Our San Jose crews know these product lines well enough to tell you honestly which one fits your lot, your timeline, and your budget. See the full list on our brands page.
Pricing for ADU Company in San Jose, CA
| Service | Typical range in San Jose |
|---|---|
| Detached ADU (400 – 800 sq ft) | $180,000 – $320,000 before site work |
| Attached ADU | $150,000 – $250,000 |
| Garage conversion ADU | $100,000 – $180,000 |
| Prefab ADU delivery and set | $220,000 – $350,000 |
| Home addition (400 – 800 sq ft) | $160,000 – $300,000 |
| Room addition (200 – 400 sq ft) | $90,000 – $170,000 |
| Foundation and seismic engineering | $15,000 – $35,000 |
| Site prep and utility trenching | $10,000 – $25,000 |
San Jose’s seismic requirements and the city’s permit and inspection timeline are the two biggest cost drivers beyond square footage. What Sutton ADU San Jose promises is a written price before any work starts, so you won’t discover these costs later in the project.
Neighborhoods We Serve in San Jose
Our San Jose crews work across the city, from the older central neighborhoods to the larger lots on the edges. We know which areas tend to have bigger backyards, which have stricter historic-district reviews, and which need extra foundation work.
- Naglee Park
- Rose Garden
- Willow Glen
- Almaden Valley
- Evergreen
We schedule San Jose estimates within a few days of your call, and our office coordinates dispatch so you’re not waiting weeks to get a walkthrough.
Service Area – Cities Near San Jose
While this page covers San Jose specifically, our crews also work in neighboring cities across the South Bay and Peninsula. If your property is outside the city line, you can find nearby coverage on our Santa Clara, CA, Cupertino, CA, Mountain View, CA, and Atherton, CA pages.
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
San Jose typically processes ADU permit applications within 60 days when the project meets state standards for a ministerial review, but discretionary review can add several months. We submit complete plan sets the first time, which is the single biggest factor in avoiding delays. Call (669) 444-4530 and we’ll give you a realistic timeline for your specific lot.
Some San Jose HOAs and planned developments have covenants that limit or prohibit ADUs, though state law overrides many restrictions. We review your HOA’s CC&Rs before you spend money on plans, because fighting a covenant after construction starts is the most expensive way to learn about one.
Yes, if the city’s minimum lot size and setback rules allow it. San Jose has specific ADU standards for lots under 5,000 square feet, and we work within them regularly, often with attached units or conversions rather than detached structures. Call (669) 444-4530 for a free estimate and we’ll tell you what your lot qualifies for.
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
"They handled the drawings and the permit paperwork for us. All I had to do was pick the finishes."
- Rosa M."Every crew member was vetted and carried a badge, which matters when they are around your family for months. Tidy site every day."
- Daniel F."Straight answers on what we could and couldn't do on our lot."
- Edwin H.
