Transform Your Property with Quality ADU Construction
Property owners throughout San Jose, CA are discovering that adding an accessory dwelling unit is one of the most practical investments they can make. ADU construction opens the door to a powerful 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 skill and transparency.
The interest in ADU construction has increased significantly in recent years, and it's easy to understand why. California state law has streamlined permitting for homeowners to build these secondary units, and local municipalities like San Jose have supported the trend as a way to expand the housing supply. If you're planning a detached backyard cottage, a garage conversion, or an attached addition, ADU construction provides increased control over how your property functions.
At Brother & Brother Builders, we draw on extensive hands-on experience to every ADU construction project. Our team knows the San Jose building codes, the engineering considerations, and the aesthetic decisions that make an ADU beautiful. Should you want to learn about what ADU construction could do for your property, this guide covers everything you need to know.
What Is the ADU Construction Process?
ADU construction refers to the process of designing, permitting, and building 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 access point — that is located on the same parcel as a primary residence. ADU construction can take several forms, including detached backyard units, attached additions, garage conversions, and even basement or interior conversions.
Mechanically, the work starts with a comprehensive review of your lot, where our builders evaluate property boundaries, available square footage, and infrastructure capacity. From there, blueprints are prepared and submitted to the local building department. Once approvals are in place, 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.
What separates excellent ADU construction from an average project is the attention to detail at every stage. Components should be specified to match the primary home's aesthetic. Systems like wiring and water supply must be built for long-term residential demand. Brother & Brother Builders treats each project with the same high standards we use on major custom home projects.
Key Reasons to Choose ADU Construction
- Increased Property Value — 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 is leasable as a long-term rental or short-term vacation unit, providing a consistent income stream for the homeowner.
- Housing for Extended Family — ADU construction gives aging parents a private, independent living space without losing proximity to the family.
- Design Flexibility — From two-bedroom configurations, ADU construction may be customized to the intended occupant's lifestyle.
- Faster Permitting in California — Recent state legislation has minimized the red tape associated with ADU construction, creating a path that is faster and more cost-efficient than ever before.
- Sustainable Land Use — 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 creates a truly separate unit where residents have their own space.
- Long-Term Investment Security — A well-built ADU holds its value for decades, providing both livable square footage and monetary benefit.
The ADU Construction Procedure Step by Step
- Initial Property Assessment and Feasibility Review — 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 ADU types will work before any time is invested in drawings.
- Blueprint Development and Layout Design — Experienced draftspeople create detailed floor plans based on your goals. Space is thoughtfully allocated to maximize function and livability.
- Permit Submission and Municipal Review — 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, addressing any city comments promptly.
- Excavation and Foundation Installation — Once permits are issued, physical construction begins. This includes grading the site, pouring the concrete foundation, and establishing utility connections.
- Framing, Roofing, and Exterior Work — The structural frame is erected followed by weatherproofing and exterior finish materials. At this stage, the ADU transforms from a concept to a building.
- Interior Systems and Infrastructure — Licensed subcontractors install the heating, cooling, drainage, and power infrastructure that make the ADU fully functional. Every system is reviewed at required milestones throughout ADU construction.
- Finishes, Fixtures, and Final Walkthrough — Countertops, hardware, finishes, and fixtures are fitted and completed to your specifications. A final city inspection confirms the unit is code-compliant 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 generally fit within a few common profiles. If you own a single-family home with available square footage under zoning rules, you're already well-positioned. Homeowners wanting to add a revenue stream through rental are among the most financially driven ADU construction clients, along with families supporting elderly parents.
Another strong candidate is someone who runs a small business and wants a private work environment that doesn't interfere with your family's daily life. Landlords and real estate investors who want to maximize their land are also prime candidates for ADU construction, since rental income frequently offsets build costs.
Situations where ADU construction may not be the best first step include properties with significant setback limitations. Sites with underground infrastructure conflicts may require additional review. Brother & Brother Builders reviews each property case by case to provide realistic options.
ADU Construction Frequently Asked Questions
How long does ADU construction usually take from start to finish?
The full timeline for ADU construction usually runs between six to fourteen months, based on the project scope and city review schedules. City review on its own can take a significant portion of the overall timeline in San Jose, so beginning the process sooner rather than later is wise. Smaller detached units can move faster, while larger new construction ADUs require more time.
What does ADU construction usually run in terms of budget?
Budget requirements differ based on the type and size of the ADU. In the San Jose area, ADU construction commonly costs $150,000 to $400,000 or more for a standalone backyard unit. Interior conversion projects are generally priced lower, sometimes between $75,000 and $140,000. An accurate budget can only be given after completing a thorough property review.
Is ADU construction disruptive while it's underway?
The day-to-day impact depends on the project's location on your property. Detached backyard builds are generally the least intrusive, since work happens away from the main house. Projects that connect to the main structure may involve some shared wall work during key milestones. Our team communicates clearly about any phases that may affect your routine.
Do I need to move out during ADU construction?
For the majority of homeowners, you are not required to vacate your main home during ADU construction. Most builds are structured to allow you stay in your primary unit throughout the process. There are edge cases if interior conversion work touches shared systems in ways that temporarily impact livability. The team at Brother & Brother Builders will walk you through any potential disruptions during the planning phase.
How long will an ADU built through professional ADU construction last?
A well-built ADU is designed to last as long as any standard residential structure — indefinitely with proper upkeep. Longevity is tied to the standard of construction, how well routine maintenance is performed, and if mechanical components are maintained on schedule. Brother & Brother Builders specifies commercial-grade materials and build to current California residential standards to ensure lasting performance.
ADU Construction for Local Homeowners
San Jose's neighborhoods offer a variety of property types that website are ideally positioned for ADU construction. Homeowners in the Willow Glen neighborhood often discover their properties are well configured for ADU builds. Communities around the Capitol Expressway corridor have seen growing ADU activity as multigenerational living becomes more common. Whether your property is near downtown San Jose, our team has likely worked nearby.
San Jose's permitting office follows defined procedures 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. Brother & Brother Builders' experience across the San Jose permitting environment means more accurate timelines and budgets from design through the final walkthrough.
Book Your ADU Construction Planning Session Today
Should you be thinking about how to move forward with ADU construction, Brother & Brother Builders is the team to call. We bring years of hands-on experience in ADU construction across a wide range of project types — from small attached additions to large custom detached cottages. The process begins with a comprehensive site assessment where we learn what you're trying to accomplish and provide an honest assessment of what's achievable.
Reach out to our team to begin the conversation. Even if you're just exploring the idea, we enjoy answer questions, share examples of our work and help you take the next step. ADU construction is a significant investment — and we want to make sure it's the right one for you.
Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632