Unlock New Space with Quality ADU Construction
Property owners throughout San Jose, CA are finding that adding an accessory dwelling unit is one of the smartest investments they can make. ADU construction provides a flexible new living space on your existing property — whether you want to create a private workspace. Brother & Brother Builders has helped hundreds of local homeowners see these visions to life with craftsmanship and transparency.
The demand for ADU construction has grown rapidly in recent years, and it's no mystery. California state law now makes it easier for homeowners to add these secondary units, and local municipalities like San Jose have encouraged the trend as a way to address housing needs. Whether you're building a detached backyard cottage, a garage conversion, or an attached addition, ADU construction provides increased control over how your property serves your household.
At Brother & Brother Builders, we apply deep hands-on experience to every ADU construction project. Our team knows the San Jose building codes, the engineering requirements, and the aesthetic decisions that make an ADU beautiful. When you're ready to explore what ADU construction could look like on your property, this guide will walk you through everything you need to know.
What Is the ADU Construction Process?
ADU construction refers to the process of engineering, filing for, and completing an accessory dwelling unit on a residential property. An accessory dwelling unit is a complete living space — including a kitchen, bathroom, sleeping area, and its own access point — that exists on the same lot as a primary residence. ADU construction can take several forms, including detached backyard units, attached additions, garage conversions, and even below-grade dwelling units.
Mechanically, everything kicks off with a comprehensive review of your lot, where our professionals evaluate setbacks, zoning, utility access, and structural feasibility. From there, blueprints are prepared and submitted to the relevant municipal authority. Once permits are secured, ADU construction transitions to the physical build phase — which covers everything from foundational work, framing, mechanical systems, weatherproofing, and interior finishing. The result is a completely finished living unit attached to or separate from your main home.
What separates excellent ADU construction from an average project is the depth of planning at every stage. Products need to be chosen to align with the neighborhood's character. Systems like wiring and water supply must be built for long-term residential demand. Brother & Brother Builders handles every ADU construction job with the same high standards we apply to large-scale custom home projects.
Key Advantages ADU Construction
- Increased Property Value — ADU construction delivers real market value to your property, often generating strong equity gains 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, providing a consistent income stream for the homeowner.
- Space for Loved Ones — ADU construction offers family members a self-contained residence without leaving the property.
- Design Flexibility — From modern studio layouts, ADU construction may be customized to your household's priorities.
- Simplified Regulatory Path — Recent state legislation has cut down the barriers and delays associated with ADU construction, resulting in a timeline that is faster and more affordable than ever before.
- Sustainable Land Use — Building an ADU maximizes the land you already own instead of requiring new development, which supports broader sustainability goals.
- Independent Living Areas — Unlike a bedroom addition, ADU construction creates a truly separate unit where tenants live autonomously.
- 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 experts review your property to evaluate setbacks, lot coverage limits, and utility connections. This phase answers exactly what's possible before any resources go toward planning.
- Custom Design and Architectural Planning — Experienced draftspeople create comprehensive blueprints tailored to your needs. Space is thoughtfully allocated to maximize function and livability.
- Permitting and City Approval — ADU construction in San Jose requires submitting plans to the city's building department for review and approval. Our team handles all submissions on your behalf, addressing any city comments promptly.
- Ground Prep and Structural Base — Once permits are issued, the build starts. This involves leveling and prepping the ground, completing foundation work, and setting up utilities.
- Framing, Roofing, and Exterior Work — Framing is completed followed by roofing, siding, windows, and exterior doors. During this step, the ADU becomes recognizable as a structure.
- MEP Systems Rough-In — Certified technicians install the heating, cooling, drainage, and power infrastructure that make the ADU operationally complete. All work is inspected at designated stages throughout ADU construction.
- Interior Completion and City Sign-Off — Countertops, hardware, finishes, and fixtures are installed and finished to the approved plan. A final city inspection confirms the unit is code-compliant and the ADU is ready for use.
Who Is a Good Candidate for ADU Construction?
People who see the greatest return from ADU construction typically fall into a few recognizable groups. If you have a residential property with available square footage under zoning rules, you're already in a good starting place. 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.
You may also be someone who needs a dedicated professional workspace and wants a separate office or studio space that is distinct 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 sites with unusual utility access challenges. Very small lots or properties with easements may need a modified approach. Our team can assess each property case by case to provide realistic options.
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, influenced by the type of unit being built and local permitting timelines. The approval phase alone can take several months in San Jose, so starting early is important. Smaller detached units may complete more quickly, while larger new construction ADUs require more time.
What does ADU construction usually run in terms of budget?
Costs vary widely based on project complexity and finishes selected. Locally, ADU construction commonly costs $150,000 to $400,000 or more for a standalone backyard unit. Interior conversion projects often come in under, sometimes starting around $80,000 depending on scope. A precise cost projection can only be produced following a formal feasibility evaluation.
Is ADU construction difficult to live through while it's underway?
The level of disruption depends on the project's location on your property. New construction in the rear yard are generally the least intrusive, since the construction zone is separate. Garage conversions or attached additions may involve some shared wall work during key milestones. Our team communicates clearly about what to expect at each stage.
Do I need to leave my home during ADU construction?
In most cases, you won't have to vacate your main home during ADU construction. Most builds are structured to allow you remain on the property throughout the process. Exceptions may arise if major utility click here upgrades affect the main house in ways that require short-term access disruption. Our project managers will discuss these scenarios during the kickoff meeting.
How long will an ADU built through professional ADU construction last?
Any ADU built to code with professional oversight should last as long as your primary home — often several decades with routine maintenance. Longevity is tied to the standard of construction, how well routine maintenance is performed, and how proactively issues are resolved over time. Brother & Brother Builders specifies high-quality components and build to current California residential standards to deliver a structure that stands the test of time.
ADU Construction for Local Homeowners
Residential areas across San Jose present a diverse mix 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. 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.
Local regulatory bodies in this area applies particular standards for ADU construction that our team navigates routinely. 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 fewer surprises from design through the final walkthrough.
Book Your ADU Construction Consultation Today
Should you be thinking about how to move forward with ADU construction, Brother & Brother Builders is the team to call. Our experts offer licensed expertise in ADU construction across a wide range of project types — from small attached additions to multi-room backyard residences. The process begins with a comprehensive site assessment where we learn what you're trying to accomplish and share clear expectations of what ADU construction on your property will look like.
Contact Brother & Brother Builders to schedule a site visit. Whether you're in the early stages of planning, we're glad to discuss timelines, costs, and design possibilities and help you take the next step. Building an ADU is a major decision — 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