Expand Your Home with Quality ADU Construction
Families in San Jose, CA are discovering that adding an accessory dwelling unit is one of the most rewarding investments they can make. ADU construction provides a versatile new living space on your existing property — whether you want to create a private workspace. Brother & Brother Builders has guided hundreds of local homeowners see these visions to life with skill and integrity.
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 build these secondary units, and local municipalities like San Jose have encouraged the trend as a way to address housing needs. Whether you want to build a detached backyard cottage, a garage conversion, or an attached addition, ADU construction gives you more control over how your property serves your household.
At Brother & Brother Builders, we apply deep hands-on experience to every ADU construction job. Our team is familiar with city and county requirements, the engineering requirements, and the aesthetic decisions that make an ADU functional. When you're ready to explore what ADU construction could look like on your property, this guide explains everything you need to know.
What Is an ADU Build?
ADU construction involves the process of designing, permitting, and building an accessory dwelling unit on a residential property. An accessory dwelling unit is a self-contained living space — equipped with a kitchen, bathroom, sleeping area, and its own access point — that sits on the same property as a primary residence. ADU construction comes in multiple configurations, including detached backyard units, attached additions, garage conversions, and even interior space reconfigurations.
Mechanically, the process begins with a thorough property evaluation, where our team evaluate lot dimensions, existing structures, soil conditions, and local code requirements. From there, architectural drawings are prepared and submitted to the city for permit approval. Once approvals are in place, ADU construction moves into the physical build phase — which covers everything from foundational work, framing, roofing, plumbing, electrical, insulation. The result is a completely finished living unit adjacent to or detached from your main home.
What sets quality ADU construction apart is the depth of planning at every stage. Materials must be selected 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 technical discipline we bring to full custom home projects.
Key Benefits ADU Construction
- Higher Resale Potential — ADU construction adds measurable market value to your property, often increasing appraised value substantially when it's time to sell.
- Monthly Cash Flow — A completed ADU may be listed as a long-term rental or short-term vacation unit, generating steady monthly revenue for the homeowner.
- Multi-Generational Living — ADU construction gives aging parents a self-contained residence without moving to another neighborhood.
- Customization Options — From modern studio layouts, ADU construction is adaptable to your specific needs.
- Simplified Regulatory Path — Recent state legislation has reduced the barriers and delays associated with ADU construction, creating a path that is faster and more cost-efficient than ever before.
- Efficient Use of Your Lot — Building an ADU uses your existing lot instead of expanding urban sprawl, which aligns with sustainability goals.
- Separate Entrances and Spaces — Unlike a bedroom addition, ADU construction creates a truly separate unit where occupants have full privacy.
- Lasting Financial Benefit — A well-built ADU holds its value for many years and generates both usable housing and equity growth.
The ADU Construction Procedure Step by Step
- Property Walkthrough and Feasibility Check — Our team visits 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.
- Blueprint Development and Layout Design — Experienced draftspeople create detailed floor plans tailored to your needs. Layouts are carefully considered to create practical, comfortable living.
- Permitting and City Approval — ADU construction in San Jose demands documentation to the city's building department for inspection and clearance. Brother & Brother Builders coordinates the permitting on your behalf, responding to review feedback promptly.
- Excavation and Foundation Installation — Once permits are approved, the build starts. This includes grading the site, completing foundation work, and establishing utility connections.
- Framing, Roofing, and Exterior Work — The structural frame is erected followed by roofing, siding, windows, and exterior doors. At this stage, the ADU becomes recognizable as a structure.
- Interior Systems and Infrastructure — Licensed subcontractors install the heating, cooling, drainage, and power infrastructure that make the ADU operationally complete. Inspections are completed at designated stages throughout ADU construction.
- Finishes, Fixtures, and Final Walkthrough — Countertops, hardware, finishes, and fixtures are installed and finished to the agreed design. A last official inspection grants legal occupancy status and the ADU is ready for use.
Who Is a Strong Candidate for ADU Construction?
Property owners who are best suited from ADU construction generally fit within a few clear categories. If you own a single-family home with a backyard, garage, or basement that could be converted, you're already a strong candidate. Homeowners hoping to offset mortgage costs through rental are among the most motivated ADU construction clients, along with families accommodating adult children who need housing.
ADU construction also suits someone who works from home and wants a separate office or studio space that remains away from your family's daily life. Landlords and real estate investors who already own residential properties are also a natural fit for ADU construction, since rental income frequently offsets build costs.
Situations where ADU construction may not be the best first step include sites with unusual utility access challenges. Very small lots or properties with easements may face additional constraints. Brother & Brother Builders reviews each property individually and honestly to recommend the right path forward.
ADU Construction Common Questions Answered
How long does ADU construction usually take from start to finish?
The full timeline for ADU construction typically ranges from six to fourteen months, based on the project scope and how quickly approvals come through. The approval phase alone can take a significant portion of the overall timeline in San Jose, so planning ahead matters. Straightforward interior conversions often finish in the lower end of the range, while custom detached builds fall toward the upper end of the timeline.
What does ADU construction usually run in terms of budget?
Pricing depends on many factors based on project complexity and finishes selected. Locally, ADU construction commonly costs $150,000 to $400,000 or more for a detached new build. Attached ADU additions tend to cost less, sometimes between $75,000 and $140,000. A detailed estimate can only be given after completing a thorough property review.
Is ADU construction disruptive while it's underway?
How much the build affects daily life depends on the project's location on your property. New construction in the rear yard are typically less disruptive, since the crew operates at a distance from your living areas. Interior conversions may require temporary access during certain phases of construction. Our team communicates clearly about what to expect at each stage.
Do I need to vacate the property during ADU construction?
Generally speaking, you are not required to vacate your primary residence during ADU construction. The vast majority of projects are designed so that you continue living in the home throughout the construction timeline. There are edge cases if major utility upgrades affect the main house in ways that require short-term access disruption. Our construction supervisors will walk you through any potential disruptions during the planning phase.
How long will an ADU built through professional ADU construction last?
An ADU constructed with quality materials should last as long as your primary home — typically 50 years or more. Longevity is tied to the quality of materials used, whether the unit is properly cared for, and if mechanical components are maintained on schedule. Our builds use commercial-grade materials and comply with all local building codes to deliver a structure that stands the test of time.
ADU Construction for Local Homeowners
Residential areas across San Jose present a variety of property types that are perfectly suited 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 multigenerational living becomes more common. Whether your property is near downtown San Jose, our team has likely worked nearby.
The City of San Jose's building department applies particular standards for ADU construction that require a builder familiar with local expectations. Location near major arterials like Story Road or Tully Road can affect how quickly permits are approved for a given ADU project. Our team's knowledge of these local conditions means more accurate timelines and budgets from the first meeting to the final inspection.
Schedule Your ADU Construction Assessment Today
Should you be thinking about how to move forward with ADU construction, Brother & Brother Builders is the team to call. We bring licensed expertise in ADU construction including all types of project types — from simple garage conversions to multi-room backyard residences. The process begins with a thorough and honest property review where we understand your vision and provide an honest assessment of what the project will involve.
Contact Brother & Brother Builders to begin the conversation. Whether read more you're in the early stages of planning, we enjoy walk through your options, review completed projects and help you take the next step. Building an ADU is a major decision — and we're committed to helping you get it right.
Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632