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
Lodgewick ADU San Jose builds accessory dwelling units (ADUs, or small secondary homes on your existing lot), garage conversions, and home additions across San Jose, CA. Most San Jose jobs involve ranch homes from the 1950s through 1970s on lots of 6,000 square feet or larger, which means big backyards, older electrical panels, and sewer lines that sometimes need upsizing before a foundation goes in. San Jose’s mild, wet winters and dry summers allow year-round building, though seismic code requirements shape foundation and shear wall design on every project. Call (669) 266-4319 to talk through your lot and get a written price.
Why San Jose Homes Are Different
San Jose is the largest city in Silicon Valley, and high housing costs paired with state ADU mandates have pushed accessory units into nearly every neighborhood. The city publishes expedited, pre-approved ADU plans that can shorten permitting time, but the real work happens on lots that haven’t changed much since the Eisenhower era. Many homes in Willow Glen, Cambrian, and the older core neighborhoods still sit on their original 1950s sewer laterals, which are often too shallow to handle a new bathroom or kitchen. Trenching and upsizing those lines is common before any framing starts.
Electrical is the other recurring issue. Homes built between 1950 and 1980 frequently have 100-amp panels, and a detached ADU with a kitchen, laundry, and mini-split heat pump usually pulls enough load to require a panel upgrade or a subpanel run from the main house. Side yard setbacks are tight on many of these lots, so over-garage ADUs have become a popular workaround in Willow Glen where lot coverage limits squeeze ground-up builds. We plan for these conditions from the first site visit, and they’re reflected in the written price we give before work begins, under The Kingswell Guarantee.
Our Main San Jose Services
Most San Jose homeowners reach out about one of two things: building a detached ADU in the backyard, or converting an attached garage into living space. Both routes create rentable square footage or room for family without buying a new house.
Home Addition Contractor in San Jose
A home addition in San Jose means expanding the footprint of your existing house, whether it’s a master suite, a second living area, or a larger kitchen. On the ranch homes common here, additions often tie into single-story rooflines and need foundation work engineered for seismic loads. San Jose’s dry summers keep framing on schedule, and because many backyards sit on expansive clay soil, we account for proper drainage and foundation depth before the first pour. We also handle the required permits and inspections. Home Addition Contractor in San Jose has full pricing and scope details.
Garage Conversion Contractor in San Jose
Garage conversions turn an existing attached or detached garage into a legal living space, and San Jose’s older homes are prime candidates because the garage is often underused while the lot itself can’t easily fit a new structure. We work through the specifics: seismic reinforcement of the existing walls, insulating and drywalling, running new electrical from the main panel, and addressing floor elevation so the finished space sits level with the house. Detached garage conversions in neighborhoods like Willow Glen sometimes stack a second story for a true two-level unit, but attached conversions on slab foundations are the more common path. Garage Conversion Contractor in San Jose breaks down the process and local code requirements.
ADU Builders in San Jose
A detached ADU is a new, separate small home built in your backyard. In San Jose, these units typically run from 400 to 1,200 square feet and range from studio layouts to two-bedroom designs. The city’s pre-approved ADU plan program can cut weeks off the permit timeline, and we’re familiar with those plans as well as custom designs. Because San Jose sits in a high-seismic zone, every ADU we build includes engineered shear walls and foundation ties that meet current California Building Code. Utility runs from the main house, panel capacity, and sewer lateral condition drive the pre-construction scope on nearly every San Jose ADU job. ADU Builders in San Jose covers full pricing, floor plan options, and the build timeline.
Home is where you can find more about Lodgewick’s full range of work and The Kingswell Guarantee.
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 directly with established ADU and materials brands including Tuff Shed, James Hardie, and Abodu. Siding, framing packages, and prefab shells are ordered to the San Jose job site, and we coordinate delivery windows so materials arrive when the schedule needs them. See our brands for the full list we work with.
Pricing for ADU Company in San Jose, CA
| Service | Typical range in San Jose |
|---|---|
| Detached ADU (studio, 400 – 500 sq ft) | $180,000 – $260,000 |
| Detached ADU (1-bedroom, 600 – 800 sq ft) | $220,000 – $340,000 |
| Detached ADU (2-bedroom, 900 – 1,200 sq ft) | $300,000 – $450,000 |
| Garage conversion (attached, 400 – 500 sq ft) | $90,000 – $140,000 |
| Garage conversion with second-story addition | $250,000 – $380,000 |
| Home addition (single room, 300 – 400 sq ft) | $120,000 – $190,000 |
| Home addition (primary suite, 500 – 700 sq ft) | $180,000 – $280,000 |
| Sewer lateral replacement or upsizing | $6,000 – $15,000 |
| Electrical panel upgrade (100A to 200A) | $4,000 – $8,000 |
| Foundation and seismic engineering | $10,000 – $25,000 |
What pushes price up in San Jose is usually the lot itself: shallow sewer lines in the older neighborhoods, 100-amp panels that need replacing, and clay soil that requires deeper foundation work. Every Lodgewick ADU San Jose project starts with a written line-item price before any work begins, and that number doesn’t change at the door.
Neighborhoods We Serve in San Jose
Our crews work across San Jose, from the older core neighborhoods to the newer tract developments. We know the setback rules, soil conditions, and utility quirks that vary block by block.
- Willow Glen
- Cambrian
- Evergreen
- Almaden Valley
- Rose Garden
Most San Jose neighborhoods are within a 30 to 45 minute drive for our crews, and we schedule site visits around the work already in progress nearby.
Service Area – Cities Near San Jose
Lodgewick ADU San Jose also serves homeowners in neighboring South Bay and Peninsula cities. If you’re just outside the city limits, we likely cover your area too: Milpitas, CA, Santa Clara, CA, Los Gatos, CA, and Los Altos, 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
After your free estimate and a signed agreement, plan development and structural engineering typically take 2 to 4 weeks. San Jose’s pre-approved ADU plan program can shorten city permit review to a few weeks if your lot qualifies. From there, construction usually runs 6 to 10 months for a detached ADU. Call (669) 266-4319 for a timeline specific to your lot.
Yes. We pull all required permits with the City of San Jose, schedule inspections, and stay on site until final sign-off. That includes any sewer lateral, electrical panel, and seismic engineering approvals. The permit process is part of your written price, so there are no surprise line items when the city requires something extra.
We check both on the first site visit. Shallow 1950s sewer laterals are common in Willow Glen and Cambrian, and many homes still run 100-amp panels. If upgrades are needed, they’re listed as separate line items in your written price before you sign anything. Call (669) 266-4319 to schedule a free estimate and site assessment.
Call Lodgewick ADU San Jose at (669) 266-4319 to schedule your free estimate. We’ll walk your lot, answer questions about San Jose-specific conditions, and put a written price in your hands before any work starts. A live person answers every call, day or night.
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
"Converted our garage into a rental studio. The crew was respectful of the neighbors and kept the site clean. It's bringing in rent now and paid for itself faster than I expected."
- Grace Yoon"Built a backyard unit for my mother in law. They handled the permits, gave me a real timeline, and stuck to it within a few days. The written price is what we paid, which anyone who's done construction knows is rare."
- Dennis Fairchild"Added a suite for my dad. They walked us through every cost before a hammer swung and stuck to it. The written price is what we paid, no change orders."
- Ingrid Salazar
