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 neighborhood. The best ADU builders in San Jose, CA don’t just handle permits and construction, they also guide you through each phase so you can make smart choices about layout, materials, and design details that fit your property.
This guide highlights local builders known for their proven track record and experience navigating 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.
Top ADU Builders in San Jose, CA
This list was curated by reviewing ADU builders who actively complete projects in San Jose and nearby South Bay cities. Companies were evaluated based on their project scope, specialization in ADU construction, and visibility across verified sources such as licensing records, builder portfolios, and third-party review platforms.
| Builder | Best For | ADU Types | Location |
| Valley Boutique Builders | Homeowners wanting one team to handle design, permits, and construction start-to-finish | Detached, attached, garage conversion | San Jose, Palo Alto, Los Gatos |
| ADORE Homes | Buyers who prefer choosing from preset layouts instead of fully custom design | Prefab detached ADUs | San Jose, Fremont, Cupertino |
| Anura Design
Architectural |
Early-stage homeowners needing architectural plans before hiring a builder | Garage conversions, additions, ADU plans | San Jose, Oakland, Napa |
| Canyon Design Build | Properties with site challenges like slopes, tight lots, or structural constraints | Detached ADUs, conversions, additions | Oakland, Piedmont, Lafayette |
| ExpandADU | Fast backyard unit installation with factory-built structures | Modular detached ADUs | San Jose, Sunnyvale, Redwood City |
| Darco Design Construction | Large remodel projects where an ADU is part of a broader home upgrade | Attached ADUs, structural additions | San Jose, Campbell, Santa Clara |
| DevArt8 Builders | Design-focused homeowners prioritizing modern exterior and interior styling | Detached backyard ADUs | San Jose, Saratoga, Cupertino |
| BetterBuilt Builders | Families converting garages or unused space into livable units | Garage conversions, attached ADUs | San Jose, Milpitas, Sunnyvale |
| In Level Construction Inc | Budget-conscious projects focused on functional secondary living space | Attached ADUs, interior conversions | San Jose, Fremont, Hayward |
| Modular Remodeling and Design | Buyers exploring prefab or hybrid construction approaches | Modular ADUs, detached units | San Jose, Mountain View, Santa Clara |
| Nova Builders Inc | Permit-heavy builds requiring coordination with city requirements | Detached ADUs, garage conversions | San Jose, Campbell, Los Gatos |
| Regalados Construction Inc | Smaller backyard units or junior ADUs on tighter residential lots | JADUs, compact conversions | San Jose, Morgan Hill, Gilroy |
| San Jose ADU Solutions | Turnkey ADU builds from planning through final construction | Detached ADUs, JADUs | San Jose, Sunnyvale, Santa Clara |
| Sami and Sons Construction | Multi-generational housing setups or guest living suites | Detached ADUs, attached suites | San Jose, Milpitas, Fremont |
| Pacific Gates Construction | Major property expansions combining | ADUs with structural upgrades
Attached ADUs, second-story additions |
San Jose, Palo Alto, Redwood City |
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
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 combines architectural design, engineering, permitting, and construction under one roof.
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.
The team 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
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
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
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
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
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. DevArt8 Builders
Areas Served: San Jose, Santa Clara, Campbell
DevArt8 Builders is a San Jose-based residential contractor that works on remodels, additions, and ADU construction projects. Their team supports homeowners through planning, permitting coordination, and construction execution. They often take on kitchen and interior remodel projects alongside ADU work for homeowners looking to upgrade multiple parts of their property at the same time.
Construction Services:
- ADU construction and home additions
- Kitchen and interior remodeling
- Permit coordination support
- Project planning and on-site construction
What Customers Are Saying:
- “They were clear about the process, realistic about timelines, and didn’t overpromise.” – verified review
- “They explained things in a way that was easy to follow.” – verified review
8. BetterBuilt Builders
Areas Served: Milpitas, San Jose, Fremont
BetterBuilt Builders is a general contractor serving South Bay homeowners with remodeling, renovation, and residential construction services. Their work includes kitchens, bathrooms, and broader home improvement projects, with some homeowners engaging them for structural upgrades and layout changes that can align with ADU goals. They position themselves as a start-to-finish contractor managing scheduling, trades, and day-to-day build coordination.
Construction Services:
- Home remodeling and renovation
- Kitchen and bathroom upgrades
- General construction and structural improvements
- Project management and trade coordination
What Customers Are Saying:
- “BBB completed my house renovation (750 sq ft expansion, kitchen renovation, flooring, roofing, 2.5 bath renovation and build) in 2023.” – verified review
- “We worked with Better Built Builders (BBB) on a major home renovation.” – verified review
9. In Level Construction Inc
Areas Served: San Jose, Morgan Hill, Gilroy
In Level Construction Inc is a residential builder that works on ADUs, custom homes, and major remodels across South Bay properties. Their team offers a full-service approach that can include design coordination, structural work, and construction management depending on project scope. They handle both attached and detached units while also taking on broader home expansion or rebuild projects.
Construction Services:
- ADU construction and custom home builds
- Home additions and major remodels
- Roofing and exterior construction work
- Project coordination from planning through build
What Customers Are Saying:
-
- “Sergiu and his team provide full service construction and renovation.” – verified review
- “He handled the renovation of our entire house.” – verified review
10. Modular Remodeling and Design
Areas Served: San Jose, Santa Clara, San Mateo County
Modular Remodeling and Design focuses on full-scope residential projects including ADUs, additions, and whole-home remodels. They emphasize taking on larger renovations where homeowners want structured timelines and centralized project oversight. Their process can involve planning support, interior design guidance, permitting coordination, and construction under one team to handle upgrades.
Construction Services:
- ADU planning and construction
- Home additions and full remodels
- Interior design and finish selection support
- Permit handling and inspection coordination
What Customers Are Saying:
- “Modular Remodeling and Design recently remodelled my kitchen and three bathrooms in San Jose.” – verified review
- “Idan was great, being communicative, present and reliable.” – verified review
11. Nova Builders, Inc.
Areas Served: San Jose, Santa Clara, Sunnyvale
Nova Builders Inc. is a residential construction company that works on ADUs, home additions, and full remodels across Silicon Valley properties. Their team handles planning guidance, permitting coordination, and construction execution depending on the homeowner’s goals. They take on both structural upgrades and new detached living spaces for clients looking to expand usable square footage.
Construction Services:
- ADU construction and detached unit builds
- Home remodeling and room additions
- Permit support and pre-construction planning
- Interior and exterior renovation work
What Customers Are Saying:
- “They were professional, on time, on budget, and wonderful to work with.” – verified review
- “Nova Builders helped to fix some hardwood flooring that was water damaged.” – verified review
12. Regalados Construction Inc.
Areas Served: San Jose, Milpitas, Fremont
Regalados Construction Inc. is a general contracting firm that handles ADUs, kitchen and bath remodels, and broader residential construction projects. They also take on custom carpentry and structural improvements tied to larger renovation plans. Their work involves site preparation, framing, finish work, and project coordination for homeowners updating or expanding existing homes.
Construction Services:
- ADU and residential construction projects
- Kitchen, bathroom, and interior remodels
- Framing and finish carpentry work
- Project oversight from prep through completion
What Customers Are Saying:
- “They completed a garage apartment conversion on my property.” – verified review
- “Great communication.” – verified review
13. San Jose ADU Solutions
Areas Served: San Jose, Milpitas, Santa Clara
San Jose ADU Solutions focuses specifically on building accessory dwelling units and guiding homeowners through the steps required to add legal secondary housing on their property. Their work includes helping clients understand zoning requirements, prepare sites for construction, and move projects through permitting and build phases. They take on detached ADUs and conversion-style projects for homeowners.
Construction Services:
- Detached ADU construction and garage conversions
- Site preparation and foundation work
- Permit coordination and zoning guidance
- Full ADU project management
What Customers Are Saying:
- “These guys are experienced contractors.” – verified review
- “These guys did great work on my sisters house a few months ago.” – verified review
14. Sami and Sons Construction
Areas Served: San Jose, Campbell, Los Gatos
Sami and Sons Construction is a family-run residential contractor that works on ADUs alongside kitchen remodels, bathroom renovations, and custom home construction. Their projects typically involve structural updates, interior finish work, and overall project coordination for homeowners upgrading or expanding existing properties. They take on both stand-alone ADU builds and larger renovation plans tied to home improvement goals.
Construction Services:
- ADU construction and home additions
- Kitchen and bathroom remodeling
- Custom home building and renovation
- Project oversight from planning through completion
What Customers Are Saying:
- “We recently completed our front porch remodel.” – verified review
- “We had Sami and Sons do a full remodel of our kitchen between 2022 and 2023.” – verified review
15. Pacific Gates Construction
Areas Served: San Jose, Santa Clara, Gilroy
Pacific Gates Construction is a family-owned residential contractor that works on remodels, custom builds, and home expansion projects across South Bay neighborhoods. Their projects involve structural upgrades, interior renovations, and construction coordination depending on the homeowner’s scope and goals. They also do ADU-related work as part of broader property improvement plans.
Construction Services:
- ADU and residential construction projects
- Kitchen and bathroom remodeling
- Custom home construction and additions
- Project oversight from planning through completion
What Customers Are Saying:
- “They did a kitchen remodel for me.” – verified review
- “They are doing a complete bathroom remodel for us.” – verified review
How to Choose the Right ADU Builder in San Jose
Choosing an ADU builder goes deeper than comparing prices or timelines on a spreadsheet. You’ll be working closely with this team for months, and the work they complete will affect your home for years. So, it’s worth slowing down early on to make sure your expectations truly align before construction begins.
Match the Builder to Your ADU Type
Not every builder approaches ADUs the same way. Some specialize in fully custom detached units that require new foundations and site planning, while others focus on prefab installations or garage conversions where space and utility connections already exist. Make sure the builder regularly handles your specific ADU type to prevent design compromises, budget surprises, or construction slowdowns once work begins.
Understand Who Handles Design, Permits, and Construction
Before signing anything, it’s important to understand who will actually manage each step of your project. Some homeowners end up coordinating separate designers, permit consultants, and contractors, which can lead to mixed timelines or unclear responsibility if issues arise. Work with a team that clearly defines or handles design development, city submissions, and construction.
Look for San Jose Permit Experience
San Jose has clear ADU pathways, but that doesn’t mean approvals are automatic. Builders who regularly work in the city understand how setbacks, height limits, utility tie-ins, and review timelines can affect design decisions early on. Choosing a team familiar with local requirements can help reduce revision cycles, avoid unnecessary plan changes, and keep your project moving more steadily through the approval process.
Compare Communication and Project Scope
An ADU project involves dozens of small decisions, from window placement to finish selections and inspection scheduling. Some builders provide frequent updates and walk you through trade-offs as they come up, while others take a more hands-off approach once construction begins. Ask how often you’ll receive updates, who your main point of contact is, and what’s included in the project scope so the overall experience feels manageable.
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.
