Transform Your Property with Expert ADU Construction
Property owners throughout San Jose, CA are realizing that adding an accessory dwelling unit is one of the smartest 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 popularity of ADU construction has grown rapidly in recent years, and it's not hard to see why. California state law has streamlined permitting for homeowners to construct these secondary units, and check here local municipalities like San Jose have supported 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 functions.
At Brother & Brother Builders, we apply deep hands-on experience to every ADU construction build. Our team understands the local permitting process, the engineering details, and the design choices that make an ADU functional. If you've been thinking about what ADU construction could look like on your property, this guide will walk you through everything you need to know.
What Is ADU Construction?
ADU construction refers to the process of planning, approving, and constructing an accessory dwelling unit on a residential property. An accessory dwelling unit is a complete living space — featuring a kitchen, bathroom, sleeping area, and its own entrance — 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 work starts with a comprehensive review of your lot, where our team evaluate setbacks, zoning, utility access, and structural feasibility. From there, design plans are prepared and submitted to the relevant municipal authority. Once the paperwork is cleared, ADU construction transitions to the physical build phase — which encompasses site preparation, framing, mechanical systems, weatherproofing, and interior finishing. The result is a fully functional living unit attached to or separate from your main home.
The difference between a good and a great ADU build is the level of craftsmanship at every stage. Materials must be selected to match the primary home's aesthetic. Systems like HVAC and drainage must be sized for independent daily use. Brother & Brother Builders approaches every build with the same professional rigor we apply to large-scale custom home projects.
Key Advantages ADU Construction
- Higher Resale Potential — ADU construction adds measurable market value to your property, often generating strong equity gains when it's time to sell.
- Revenue Generation — A completed ADU can be rented as a long-term rental or short-term vacation unit, providing a consistent income stream for the homeowner.
- Space for Loved Ones — ADU construction offers family members a private, independent living space without moving to another neighborhood.
- Customization Options — From open-plan one-bedrooms, ADU construction is adaptable to the intended occupant's lifestyle.
- Simplified Regulatory Path — Recent state legislation has cut down the red tape associated with ADU construction, making the process that is faster and more cost-efficient than ever before.
- Responsible Property Development — Building an ADU maximizes the land you already own instead of requiring new development, which contributes to sustainability goals.
- Separate Entrances and Spaces — Unlike a bedroom addition, ADU construction produces a fully self-contained unit where residents have their own space.
- Long-Term Investment Security — A well-built ADU holds its value for many years and generates both functional space and financial upside.
The ADU Construction Process Step by Step
- Site Evaluation and Zoning Analysis — Our builders assess your property to analyze zoning rules, slope conditions, and available square footage. This step tells you exactly what can be built before any time is invested in drawings.
- Custom Design and Architectural Planning — Licensed architects and designers create detailed floor plans based on your goals. Layouts are carefully considered to create practical, comfortable living.
- Permit Submission and Municipal Review — ADU construction in San Jose requires submitting plans to the city's building department for inspection and clearance. Our team handles all submissions on your behalf, addressing any city comments promptly.
- Ground Prep and Structural Base — Once permits are approved, on-site work kicks off. This includes grading the site, pouring the concrete foundation, and establishing utility connections.
- Framing, Roofing, and Exterior Work — Framing is completed followed by weatherproofing and exterior finish materials. At this stage, the ADU takes its visible shape.
- Interior Systems and Infrastructure — Skilled tradespeople install the heating, cooling, drainage, and power infrastructure that make the ADU fully functional. Every system is reviewed at each code checkpoint throughout ADU construction.
- Interior Completion and City Sign-Off — Trim, appliances, tile, and lighting are placed and inspected to your specifications. A closing municipal review grants legal occupancy status and your new space is cleared for use.
Who Is a Strong Candidate for ADU Construction?
People who see the greatest return from ADU construction generally fit within a few clear categories. If you own a single-family home with enough lot space to meet setback requirements, you're already well-positioned. Homeowners looking to generate income through rental are among the most common ADU construction clients, along with families supporting elderly parents.
ADU construction also suits someone who works from home and wants a detached creative or business space that remains away from your family's daily life. Landlords and real estate investors who already own residential properties are also well suited for ADU construction, since the return on investment is well-documented.
Those who should discuss alternatives first include lots that are below minimum size thresholds. Parcels in historic districts or HOA-restricted communities may require additional review. Our experts will evaluate each property case by case to advise you on what's feasible.
ADU Construction FAQ
How long does ADU construction usually take from start to finish?
The total process for ADU construction commonly spans six to fourteen months, based on the project scope and local permitting timelines. City review on its own can take two to four months in San Jose, so starting early is important. Simpler garage conversions may complete more quickly, while larger new construction ADUs require more time.
What does ADU construction usually run in terms of budget?
Pricing depends on many factors based on whether it's a conversion or new construction. Locally, ADU construction commonly costs $150,000 to $400,000 or more for a fully custom construction. Attached ADU additions tend to cost less, sometimes starting around $80,000 depending on scope. A detailed estimate can only be developed after a thorough property review.
Is ADU construction difficult to live through while it's underway?
The level of disruption depends on the project's location on your property. Detached backyard builds are typically less disruptive, since the construction zone is separate. 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 house during ADU construction. The vast majority of projects are designed so that you remain on the property 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?
Any ADU built to code with professional oversight is designed to last as long as your primary home — indefinitely with proper upkeep. Longevity is tied to the quality of materials used, how consistently minor repairs are addressed, and if mechanical components are maintained on schedule. Our builds use high-quality components and build to current California residential standards to protect your investment for the long haul.
ADU Construction for Local Homeowners
Residential areas across San Jose present a wide range of property types that are well suited for ADU construction. Residents in the Rose Garden district frequently see their parcels work well for both attached and detached projects. The Berryessa area have seen growing ADU activity as multigenerational living becomes more common. If you're located closer to Evergreen, 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. Proximity to transit corridors can impact the design approach for a given ADU project. Brother & Brother Builders' experience across this region's building landscape means more accurate timelines and budgets from kickoff through certificate of occupancy.
Schedule Your ADU Construction Assessment Today
Should you be thinking about how to add an ADU to your property, Brother & Brother Builders is ready to guide you. We bring licensed expertise in ADU construction across a wide range of project types — from modest studio builds to multi-room backyard residences. The process begins with a comprehensive site assessment where we listen to your goals and give you a realistic picture of what the project will involve.
Contact Brother & Brother Builders to begin the conversation. Whether you're in the early stages of planning, we're glad to walk through your options, review completed projects and make sure you feel confident before committing. Building an ADU is a major decision — and our goal is to ensure it delivers real value.
Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632