If you’re planning to build an accessory dwelling unit (ADU) in San Jose, you already know how valuable the extra space can be. They’re great for adding a backyard home for family, a private rental unit, or a quiet studio that finally gives you room to breathe.
San Jose allows several types of ADUs, including detached or attached ADUs, smaller junior ADUs (JADUs) that connect to the main home, and tiny homes on wheels (THOWs) for movable living. However, finding a builder who understands your goals and the city’s unique rules is where most homeowners get stuck.
That’s why it helps to work with a builder who’s already done it dozens of times in your neighborhoods. The best ADU builders in San Jose, CA don’t just handle permits and construction, they also guide you through each phase so make smart choices about layout, materials, and design details that fit your property.
This guide highlights local builders known for their proven track record of experience with San Jose’s ADU process. Whether you’re starting from an empty backyard or converting an existing garage, these are the teams that can help turn your plan into a finished home.
Benefits of Building an ADU in San Jose
Building an ADU in San Jose comes with more upside than most homeowners realize. Beyond adding square footage, it’s a way to make your existing land more useful and valuable.
The right ADU builder can help you:
- Give family their own space while still keeping them close.
- Turn your backyard into a rental that helps offset your mortgage.
- Add instant value to your property with a fully permitted second unit.
- Create a quiet studio, home office, or guest suite that adds to your lifestyle.
- Maximize your property’s space without losing privacy or outdoor areas.
- Build something that adapts to life changes like aging parents, adult kids, or future tenants.
Top ADU Builders in San Jose, CA
Whether your goal is to bring family closer, earn steady rental income, or simply make better use of your property, these custom home builders can help make it happen. Each one offers hands-on guidance to bring your vision to life.
1. Valley Boutique Builders
Areas Served: Cupertino, Los Altos, Los Altos Hills, Los Gatos, Menlo Park, Palo Alto, Portola Valley, San Jose, Santa Clara, Saratoga, Sunnyvale, Woodside, Atherton
Years in Business: 10+
Valley Boutique Builders is a full-service design-build firm specializing in custom ADUs, home renovations, and new construction across the Peninsula and South Bay. Led by husband and wife founders Roi and Ofir, the team comes with strong architectural design, engineering, permitting, and construction under one roof. This way, homeowners have a single, transparent process from start to finish.
Every ADU is tailored to the property and its use, whether it’s a detached backyard cottage for family, an attached suite for rental income, or a converted garage for flexible living space. By managing the entire process in-house, VBB helps clients navigate Bay Area zoning rules, site layouts, and utility requirements with fewer surprises and faster approvals. The firm is known for its clear communication, design precision, and deep familiarity with local building departments throughout Silicon Valley.
VBB is known for its meticulous attention to detail, responsiveness, and collaborative approach. The firm’s reputation for quality and trust has been built through word-of-mouth referrals and lasting client relationships.
Construction Services:
- ADU design and construction: Add a detached, attached, or conversion-style ADU built to city code with comfort, privacy, and long-term value.
- Custom home design and new construction: Build a ground-up residence shaped around your lifestyle, lot conditions, and architectural goals.
- Full-home renovations and remodels: Modernize older Bay Area homes with new layouts, structural upgrades, and cohesive interior design.
- Home additions and expansions: Increase livable space with single or multi-story additions that integrate with the existing structure.
- Bathrooms and kitchen remodeling: Refresh the most-used spaces with improved layouts, durable materials, and thoughtful detailing.
- Interior design and finish selection: Coordinate fixtures, flooring, and finishes for a more consistent look and smooth construction workflow.
What Customers Are Saying:
- “Roi and Ofir have done it again! This is our second project with them and once again they have blown us away.” – verified customer
- “I contacted Valley Boutique to remodel our home after a close friend who had done a similar project recommended them. Roi and Ofir demonstrated professionalism, efficiency, and competency.” – verified customer
Learn more about Valley Boutique Builders
2. ADORE Homes
Areas Served: San Jose, Fremont, Cupertino
Years in Business: 5+
ADORE Homes focuses exclusively on ADUs and offers a catalog of pre-designed ADU models that are factory-built and then installed on-site. Their process involves site assessment, permitting, factory construction, delivery, and installation that is handled through their internal team and partnered licensed contractors. They’re part of the city’s pre-approved ADU program.
Construction Services:
- Pre-designed ADU models
- ADU design and customization
- Permitting and site assessment support
- Site prep and installation
What Customers Are Saying:
- “Tom and his team coordinated how to move a pre fab unit through all the way.” – verified review
- “I was contacted on a weekly basis regarding timelines, approvals and any set backs that occurred.” – verified review
3. Anura Design
Areas Served: San Jose, Oakland, Pleasant Hill, Napa
Years in Business: 10+
Anura Design is a residential architecture and engineering firm that handles planning, design, and technical drawings for ADUs, additions, and full remodels. Their team manages zoning research, design development, and permit-ready construction documents that comply with local codes. While they don’t build in-house, they collaborate with general contractors to help homeowners move from concept to construction.
Construction Services:
- ADU design and construction documents
- Garage conversions and additions
- Permitting and plan submittal support
- Structural and MEP engineering
What Customers Are Saying:
- “If there is any “downside,” it’s simply that Romain moves quickly.” – verified review
- “All my projects with Anura never had more than 1 comment from the building departments.” – verified review
4. Canyon Design Build
Areas Served: Oakland, Piedmont, Lafayette
Years in Business: 50+
Canyon Design Build is a long-standing design-build firm that provides in-house architecture, engineering, and construction for residential projects. They work on ADUs, major remodels, and additions across different Bay Area properties, including older homes and hillside lots. Their team manages projects from initial design through permitting and construction, keeping all aspects under one roof for simpler coordination.
Construction Services:
- ADU design and construction
- Home additions and garage conversions
- Architectural and structural engineering
- Permit coordination and project management
What Customers Are Saying:
- “Most of the rooms in my house were touched or rebuilt by Canyon Design Build.” – verified review
- “They met us at convenient hours for the design phase and project check-ins.” – verified review
5. ExpandADU
Areas Served: San Jose, Sunnyvale, Redwood City
Years in Business: 3+
ExpandADU focuses exclusively on ADUs and specialises in prefabricated—factory-built—units that are transported and installed on a homeowner’s lot. Their offering covers units from roughly 325 sq ft to 1,200 sq ft, including foundation work, utility tie-ins and full install of the finished modular structure. They guide homeowners through site suitability, panel upgrade if needed, and seismic-engineered foundations.
Construction Services:
- Prefabricated ADU manufacturing and installation
- Site prep and concrete foundation work
- Utility panel and electrical upgrades
- Detached ADUs
What Customers Are Saying:
- “They provided complete end-to-end service.” – verified review
- “They were quick to come and study the site once we told them our requirements.” – verified review
6. Darco Design Construction
Areas Served: San Jose, Cupertino, Palo Alto
Years in Business: 10+
Darco Design Construction is a full-service residential and commercial builder headquartered in San Jose, CA. They offer custom homes, major remodels, and both detached and attached ADUs. They describe a start-to-finish process covering schematic design through final inspection for homeowners looking to add a self-contained unit on their property.
Construction Services:
- ADU design and build
- Custom home construction and remodels
- Permit coordination and pre-construction planning
- Interior design and luxury finish work
What Customers Are Saying:
- “We had a major kitchen and dining room remodel performed by DARCO.” – verified review
- “They estimated the project to take around 6-7 weeks and that was exactly how long it took.” – verified review
7. Elevated Edge Construction
Areas Served: San Jose, Cupertino, Sunnyvale
Years in Business: 2+
Elevated Edge Construction is a full-service residential contractor based in San Jose that works on remodels, additions, and ADUs across the South Bay. They provide both design and construction services for detached and attached ADUs, including plan development, permit coordination, and full site preparation. The company also handles utility tie-ins, foundation work, and finish construction, giving homeowners a single team to navigate zoning and build-out requirements.
Construction Services:
- Custom ADUs and JADUs
- Whole home remodels
- Permit assistance and code compliance support
- Site prep and utility coordination
What Customers Are Saying:
- “From the start to finish I was kept informed of daily updates and if they had to make any adjustments.” – verified review
- “They completed the project in a timely matter and promises and was very responsive.” – verified review
8. GPI Builders
Areas Served: Campbell, Cupertino, Los Gatos
Years in Business: 10+
GPI Builders is a full-service construction firm in the Bay Area that offers everything from home remodels to new ADU builds and outdoor hardscape. For ADUs specifically, they list both garage or basement conversions and new detached units. Their team includes masonry and electrical licenses, so they can handle site work beyond just finishing demo and replacement.
Construction Services:
- ADUs, garage, and basement conversions
- Home additions
- Kitchen and bathroom remodels
- Landscape and hardscape installations
What Customers Are Saying:
- “Crew members were hard working and daily cleanup were always done.” – verified review
- “GPI helps us with the full house remodel.” – verified review
9. Lemon Remodeling & Services Inc
Areas Served: San Jose, Palo Alto, San Mateo
Years in Business: 3+
Lemon Remodeling & Services Inc. is a design-and-build remodeling firm based in San Jose that offers room additions, whole-home remodels, and ADUs. They can convert existing space into room additions or JADUs. Lemon Remodeling also handles new construction, including the design, plan submittal, and build phases.
Construction Services:
- Room additions and ADUs
- Whole-home remodeling
- Energy-efficient upgrades
- Design, permit, and build services for remodeling
What Customers Are Saying:
- “Their crew remodeled our bathroom and laundry room, put in new flooring, and updated the lighting in our kitchen.” – verified review
- “We explained what we wanted and they were pleased to help.” – verified review
10. Century Bay Builders
Areas Served: San Jose and surrounding areas
Years in Business: 4+
Century Bay Builders is a residential contractor that focuses on home remodeling, additions, ADU projects, and new construction. Their work ranges from full interior renovations to room additions, garage conversions, and guest houses that function as separate living spaces. The team also produces construction plans and helps homeowners move from initial layout ideas through permits and full build-out on occupied properties.
Construction Services:
- ADU remodels and ground-up ADU construction
- Garage conversions and home additions
- Construction plans and permit-ready layouts
- Whole-home remodeling and interior reconfiguration
What Customers Are Saying:
- “They were clear and open about our options to complete our project of converting our garage into an ADU.” – verified review
- “We were in constant contact and they were extremely responsive.” – verified review
11. Clarity Construction
Areas Served: San Jose
Years in Business: 10+
Clarity Construction is a design-build firm that specializes in residential remodeling, additions, and new home construction. They handle projects end-to-end, combining design, planning, and construction under one team for homeowners who want a single point of contact. Their portfolio includes kitchen and bathroom renovations, full-home remodels, and projects where new square footage is added for offices, bedrooms, and secondary living spaces.
Construction Services:
- ADU-style additions and conversions
- Home additions and expansions
- Kitchen, bathroom, and full-home remodeling
- Design-build planning and construction management
What Customers Are Saying:
- “Our family worked with Daniel and his crew on our kitchen renovation.” – verified review
- “The process felt well-organized.” – verified review
12. ClearSky Builders Inc.
Areas Served: San Jose, Santa Clara, Los Altos
Years in Business: 5+
ClearSky Builders specializes in residential construction with a strong focus on custom homes and remodeling in San Jose and the nearby area. Their process begins with project planning, advances through design and construction documents, and concludes with full build-out. Although not exclusively branded as an ADU builder, their portfolio includes garage conversions and additions that function like a secondary unit.
Construction Services:
- Garage conversions and additions)
- Custom home building and large-scale remodeling
- Project planning
- Interior architecture and exterior upgrades
What Customers Are Saying:
- “The property I worked with Clarity on has undergone a complete renovation of a kitchen, baths windows, roof, HVAC, hardscape, etc.” – verified review
- “We did a full house remodel and the entire project came in on time and on budget.” – verified review
13. Prada Builders Group
Areas Served: San Jose, Sunnyvale, Mountain View
Years in Business: 15+
Prada Builders Group is a San Jose design and build firm that offers new home construction, remodels, and ADUs. For ADUs, they provide initial design concepts, architectural drawings, permit filing, and full construction of detached, attached, or interior units. They emphasize in-house coordination of project management, engineering and build crews to handle the process for homeowners working within the local regulatory environment.
Construction Services:
- Custom ADUs
- Whole-home remodels
- Home additions and room expansions
- Architectural design and permit support
What Customers Are Saying:
- “They handled everything from design to construction with professionalism.” – verified review
- “4. The construction site was always tidied up and cleaned every day.” – verified review
14. SkyTech Builders
Areas Served: San Jose, Cupertino, Sunnyvale
Years in Business: 10+
SkyTech Builders is a Bay Area general contractor that includes remodeling, additions, and ADUs among its services. In terms of ADUs, they list garage conversions, new detached units and remodel-integrated units, covering design, construction, and finish work. They allow for style choices and structural variation within an ADU or conversion project.
Construction Services:
- Garage conversions and ADUs
- Home additions and new construction
- Kitchen and bathroom remodels
- Full remodels
What Customers Are Saying:
- “We recently completed a full home remodel with Leo and Skytech Builders.” – verified review
- “They handled demolition, new walls, flooring, electrical, and plumbing.” – verified review
15. Casa Utopia Builders
Areas Served: San Jose, Campbell, Cupertino
Years in Business: 10+
Casa Utopia Builders is a licensed general contractor that offers ADU construction, home additions, and full remodels throughout the Bay Area. They handle design coordination, permitting, and ground-up construction to help homeowners add livable square footage on existing residential lots. Their projects range from detached ADUs and conversions to full interior rebuilds that rework the layout of the main home.
Construction Services:
- ADU construction and additions
- Garage conversions
- Permit coordination and design collaboration
- Interior and exterior remodeling
What Customers Are Saying:
- “Most of the rooms in my house were touched or rebuilt by Canyon Design Build.” – verified review
- “They met us at convenient hours for the design phase and project check-ins.” – verified review
16. Apex Homes
Areas Served: San Jose, Cupertino
Years in Business: 5+
Apex Homes specializes exclusively in ADUs and offers a full design–build process using pre-approved floor plans. Homeowners choose from one- or two-story layouts that can be customized to the property, while the team manages all design adjustments, permits, and construction. They’re also part of San Jose’s pre-approved ADU program, helping homeowners reduce review times and start building faster.
Construction Services:
- Pre-approved ADU floor plans
- ADU design and build
- Permit support
- Zoning support
What Customers Are Saying:
- “They made sure to walk us through every step of the process.” – verified review
- “hey also had a onsite project manager through the whole construction time.” – verified review
Choose the Right ADU Builder in San Jose
Building an ADU in San Jose is a major investment that requires a local team familiar with San Jose’s zoning, lot sizes, and permit rules.
Valley Boutique Builders brings that expertise to every project. As a husband and wife design-build team, Roi and Ofir stay involved from the first site visit to the final inspection. Their in-house process covers design, engineering, permitting, and construction, and keeps communication clear and the project on schedule.
Whether you’re adding a detached cottage, converting a garage, or starting a new build, Valley Boutique Builders delivers world-class craftsmanship and reliable organization backed by years of Bay Area experience.
Explore Valley Boutique Builders’ services today!
San Jose ADU Building FAQs
What Types of ADUs Can Be Built in San Jose?
San Jose allows three main types of accessory units: full-size ADUs, JADUs, and THOWs). Each one serves a different purpose depending on how much space you have, your budget, and what you plan to use it for.
ADUs are the most common choice. These can be detached backyard homes, attached extensions, or conversions of existing spaces like garages or basements. They function as complete homes with their own kitchen, bathroom, and entrance. Most homeowners choose this route when they want a private rental unit, a long-term home for family, or a fully independent guest house. Detached ADUs offer the most space and flexibility, but they also require more planning for utilities, setbacks, and access.
JADUs are smaller secondary units created within the footprint of the main home—often from a converted bedroom or an attached garage. They include a kitchenette and a separate entrance but share the main home’s utilities. Because they use existing square footage, JADUs are faster and more affordable to build. They work well for aging parents, adult children, or part-time rentals, though San Jose requires that the property owner live in one of the two units.
THOWs are prefabricated, movable units that sit on a trailer chassis. They’ve become a creative solution for homeowners who want extra living space without a long construction timeline. In San Jose, THOWs must meet specific size, utility, and safety standards to qualify as legal ADUs. They’re ideal for more flexible use like a backyard studio or temporary guest home, but may not suit every property because of placement and permit restrictions.
Choosing between these options often comes down to your lifestyle and long-term plans. A detached ADU adds the most value and independence, a JADU keeps costs low while maximizing your home’s footprint, and a THOW offers the most flexibility if your property qualifies.
What is the Typical Timelines for Building an ADU in San Jose?
Most projects finish between six and twelve months, depending on the complexity, design choices, and how smoothly the reviews go. Building an ADU in San Jose moves through these key stages:
- Consultation: The right ADU firm always starts with a thoughtful consultation. At Valley Boutique Builders, we listen closely to your unique goals, desired outcomes, specific questions, and budget to craft an ADU that perfectly reflects your needs.
- Planning and design: This stage is where your team will manage zoning, setbacks, and lot constraints. You’ll also begin schematic layout, material selections, and structural decisions. San Jose has specific rules for ADUs—size limits, utility connections, tree/soil issues—so characterizing your property early and choosing the right builder/architect speeds this up.
- Permitting and approvals: This is often the most unpredictable phase. In San Jose, the reviews cover land-use, building, utilities, and possibly environmental or tree-protection departments. At Valley Boutique Builders, we guide you through each step, anticipate potential review questions, and maintain close communication with city staff. Our proactive approach helps reduce delays and keeps the process moving forward with confidence.
- Material selection and finalizing design: Once permitting is underway or nearing completion, our design team helps you refine finishes, fixtures, exterior details, and key interior elements. With expert guidance, you can make choices that fit both your aesthetic and your budget, ensuring your ADU is beautiful, durable, and aligned with how you plan to use the space.
- Active construction: Foundation, framing, utilities, interior finishes, inspections and final touches happen here. Build time for many ADUs runs about four to six months for the construction portion, but that depends on scope, materials, weather and inspection flows well.
What Regulations are Required for Building an ADU in San Jose?
San Jose has one of the most ADU-friendly building departments in the Bay Area, but it still comes with a long checklist of requirements. The city follows its official ADU Universal Checklist, which outlines everything inspectors review before issuing permits.
Here are the main rules most San Jose homeowners will need to follow:
- Most single-family lots can include one detached ADU and one JADU
- Detached ADUs can be up to 1,200 sq ft, while JADUs are capped at 500 sq ft and must sit within the main home or attached garage
- Detached ADUs must be at least four feet from rear and side property lines.
- Standard maximum is 16 ft, but taller units—up to 24 ft—can be approved if they match the main home’s height and meet privacy standards.
- Extra parking is usually waived if the lot is within half a mile of transit, near a car-share, or converting existing space.
- Each unit needs approved utility tie-ins, fire separation, and compliance with Title 24 energy and solar rules.
- Every ADU requires a recorded deed restriction confirming shared ownership and owner-occupancy for JADUs.
It might sound like a lot, but at Valley Boutique builders, we handle this all for you. We’ll make sure your drawings, title sheets, and calculations align with San Jose’s requirements before anything gets submitted.
