Transform Your Property with Professional ADU Construction
Homeowners across San Jose, CA are finding that adding an accessory dwelling unit is one of the most practical investments they can make. ADU construction provides a flexible new living space on your existing property — whether you want to house a family member. Brother & Brother Builders has helped hundreds of local homeowners turn these plans to life with craftsmanship and care.
The interest in ADU construction has increased significantly in recent years, and it's no mystery. California state law has simplified the process for homeowners to construct these secondary units, and local municipalities like San Jose have supported the trend as a way to address housing needs. If you're planning a detached backyard cottage, a garage conversion, or an attached addition, ADU construction gives you more control over how your property functions.
At Brother & Brother Builders, we bring years of hands-on experience to every ADU construction project. Our team understands the local permitting process, the engineering requirements, and the planning steps that make an ADU beautiful. If you've been thinking about what ADU construction could mean for your property, this guide covers everything you need to know.
What Is the ADU Construction Process?
ADU construction involves the process of planning, approving, and constructing an accessory dwelling unit on a residential property. An accessory dwelling unit is a fully independent living space — equipped with a kitchen, bathroom, sleeping area, and its own entryway — that exists on the same lot as a primary residence. ADU construction includes various structural types, including detached backyard units, attached additions, garage conversions, and even basement or interior conversions.
Mechanically, the work starts with a thorough property evaluation, where our team evaluate property boundaries, available square footage, and infrastructure capacity. From there, design plans are prepared and submitted to the relevant municipal authority. Once approvals are in place, ADU construction moves into the physical build phase — which includes foundation work, framing, roofing, plumbing, electrical, insulation. The result is a fully functional living unit attached to or separate from your main home.
What sets quality ADU construction apart is the level of craftsmanship at every stage. Components should be specified to align with the neighborhood's character. Systems like plumbing and electrical must be sized for independent daily use. Brother & Brother Builders handles every ADU construction job with the same professional rigor we bring to full custom home projects.
Key Reasons to Choose ADU Construction
- Boosted Home Equity — ADU construction adds measurable market value to your property, often increasing appraised value substantially when it's time to sell.
- Rental Income Potential — A completed ADU can be rented as a long-term rental or short-term vacation unit, generating steady monthly revenue for the homeowner.
- Housing for Extended Family — ADU construction gives aging parents a self-contained residence without losing proximity to the family.
- Personalized Layouts — From modern studio layouts, ADU construction may be customized to your household's priorities.
- Streamlined Approval Process — Recent state legislation has cut down the red tape associated with ADU construction, resulting in a timeline that is faster and more cost-efficient than ever before.
- Responsible Property Development — Building an ADU works within your current footprint instead of expanding urban sprawl, which supports broader sustainability goals.
- Separate Entrances and Spaces — Unlike a bedroom addition, ADU construction produces a fully self-contained unit where residents have their own space.
- Durable Return on Investment — A well-built ADU continues to produce returns for decades, providing both livable square footage and monetary benefit.
The ADU Construction Journey Step by Step
- Property Walkthrough and Feasibility Check — Our builders assess your property to determine what type of ADU is allowed and where it can be placed. This step tells you exactly what's possible before any money is spent on design.
- Architectural Drafting and Space Planning — Experienced draftspeople create precise architectural drawings tailored to your needs. Space is thoughtfully allocated to create practical, comfortable living.
- Filing for Building Permits — ADU construction in San Jose demands documentation to the city's building department for review and approval. Our team handles all submissions on your behalf, responding to review feedback promptly.
- Site Preparation and Foundation Work — Once permits are issued, on-site work kicks off. This includes grading the site, laying the structural base, and setting up utilities.
- Framing, Roofing, and Exterior Work — Walls and roof systems go up followed by weatherproofing and exterior finish materials. At this stage, the ADU transforms from a concept to a building.
- Interior Systems and Infrastructure — Certified technicians install the plumbing lines, electrical wiring, and HVAC systems that make the ADU operationally complete. Every system is reviewed at each code checkpoint throughout ADU construction.
- Finishes, Fixtures, and Final Walkthrough — Countertops, hardware, finishes, and fixtures are fitted and completed to your specifications. A last official inspection grants legal occupancy status and the unit is officially approved for use.
Who Is a Strong Candidate for ADU Construction?
Property owners who are best suited from ADU construction often belong to a few recognizable groups. If you are a homeowner with a backyard, garage, or basement that could be converted, you're already in a good starting place. Homeowners looking to generate income through rental are among the most common ADU construction clients, along with families navigating multigenerational living situations.
ADU construction also suits someone who works from home and wants a detached creative or business space that doesn't interfere with your family's daily life. Real estate-minded homeowners who are building a portfolio are also a natural fit for ADU construction, since the long-term value is proven.
Homeowners who may want to pause and evaluate include sites with unusual utility access challenges. Sites with underground infrastructure conflicts may need a modified approach. Brother & Brother Builders reviews each property case by case to recommend the right path forward.
ADU Construction Common Questions Answered
How long does ADU construction usually take from start to finish?
The total process for ADU construction typically ranges from six to fourteen months, depending on design complexity and local permitting timelines. Permitting alone can take a significant portion of the overall timeline in San Jose, so starting early is important. Straightforward interior conversions may complete more quickly, while custom detached builds take longer to complete.
What does ADU construction usually run in terms of budget?
Budget requirements differ based on the type and size of the ADU. Locally, ADU construction typically ranges from $150,000 to $400,000 or more for a detached new build. Garage conversions often come in under, sometimes in the $80,000 to $150,000 range. A detailed estimate can only be developed after a thorough property review.
Is ADU construction intrusive while it's underway?
How much the build affects daily life depends on whether you're converting existing space or building new. Detached backyard builds are generally the least intrusive, since work happens away from the main house. Interior conversions may require temporary access during specific stages like framing or MEP rough-in. We provide advance notice about what to expect at each stage.
Do I need to move out during ADU construction?
In most cases, you won't have to vacate your primary residence during ADU construction. Most job sites are designed so that you remain on the property throughout the construction timeline. Certain situations could require a brief departure if significant structural connections require temporary shutoffs in ways that briefly affect habitability. Our project managers will flag these situations during the planning phase.
How long will an ADU built through professional ADU construction remain in good condition?
A well-built ADU is designed to last as long as any standard residential structure — typically 50 years or more. Durability depends to the quality of materials used, how well routine maintenance is performed, and whether systems like roofing and plumbing are serviced regularly. Our builds use residential-grade products rated for longevity and follow all code requirements to protect your investment for the long haul.
ADU Construction for Local Homeowners
Residential areas across San Jose present a variety of property types that are ideally positioned for ADU construction. Residents in the Rose Garden district frequently see their parcels work well for both attached and detached projects. Neighborhoods near Blossom Hill Road are increasingly popular for ADU construction as housing demand rises. From neighborhoods near the Guadalupe River Park corridor to those near Branham Lane, our team has project experience in the area.
The City of San Jose's building department follows defined procedures for ADU construction that experienced builders know well. Access to infrastructure along thoroughfares like Monterey Road can impact the design approach for a given ADU project. Brother & Brother Builders' experience across this region's building landscape means fewer surprises from kickoff through certificate of occupancy.
Start Your ADU Construction Assessment Today
When you want to move forward with ADU construction, Brother & Brother Builders is the team to call. Our experts offer proven skills in ADU construction including all types of project types — from small attached additions to fully independent secondary homes. The process begins with a detailed, no-pressure consultation where we learn what you're trying to accomplish and give you a realistic picture of what's achievable.
Contact Brother & Brother Builders to set up your consultation. Whether you're in the early stages of planning, we enjoy answer questions, share examples of our work and give you the clarity you need to move forward. This type of project is a meaningful commitment — and we want to make sure it's the right one for you.
Brother & Brother Builders | 3109 Stevens Creek Boulevard | San website Jose CA 95117 | (888) 412-2632