Unlock New Space with Professional ADU Construction
Homeowners across San Jose, CA are discovering that adding an accessory dwelling unit is one of the most rewarding investments they can make. ADU construction opens the door to a powerful new living space on your existing property — whether you want to create a private workspace. Brother & Brother Builders has supported hundreds of local homeowners bring these projects to life with skill and integrity.
The demand for ADU construction has grown rapidly in recent years, and it's not hard to see why. California state law has simplified the process for homeowners to add these secondary units, and local municipalities like San Jose have encouraged the trend as a way to increase density responsibly. If you're planning 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 bring years of hands-on experience to every ADU construction project. Our team is familiar with city and county requirements, the engineering requirements, and the design choices that make an ADU functional. When you're ready to explore what ADU construction could do for your property, this guide explains everything you need to know.
What Is an ADU Build?
ADU construction describes 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 — featuring a kitchen, bathroom, sleeping area, and its own entrance — that is located on the same parcel 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 detailed site assessment, where our builders evaluate setbacks, zoning, utility access, and structural feasibility. From there, architectural drawings 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, mechanical systems, weatherproofing, and interior finishing. The result is a completely finished living unit connected to or independent of your main home.
What separates excellent ADU construction from an average project is the level of craftsmanship at every stage. Products need to be chosen to match the primary home's aesthetic. Systems like wiring and water supply must be built for long-term residential demand. Brother & Brother Builders approaches every build with the same professional rigor we apply to large-scale custom home projects.
Key Reasons to Choose ADU Construction
- Higher Resale Potential — ADU construction contributes significant 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.
- Multi-Generational Living — ADU construction gives aging parents a comfortable home of their own without losing proximity to the family.
- Design Flexibility — From open-plan one-bedrooms, ADU construction is adaptable to your specific needs.
- 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.
- Efficient Use of Your Lot — Building an ADU uses your existing lot 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.
- Lasting Financial Benefit — A well-built ADU continues to produce returns for the long haul by offering both functional space and financial upside.
The ADU Construction Process Step by Step
- Initial Property Assessment and Feasibility Review — Our builders assess your property to analyze zoning rules, slope conditions, and available square footage. This phase answers exactly what's possible before any resources go toward planning.
- Architectural Drafting and Space Planning — Licensed architects and designers create comprehensive blueprints based on your goals. Every square foot is planned to maximize function and livability.
- Permit Submission and Municipal Review — ADU construction in San Jose demands documentation to the city's building department for sign-off and verification. We manage this entire process on your behalf, addressing any city comments promptly.
- Excavation and Foundation Installation — Once permits are issued, on-site work kicks off. This involves leveling and prepping the ground, completing foundation work, and setting up utilities.
- Shell Construction and Exterior Finishing — Walls and roof systems go up followed by weatherproofing and exterior finish materials. During this step, the ADU transforms from a concept to a building.
- Mechanical, Electrical, and Plumbing Installation — Skilled tradespeople install the heating, cooling, drainage, and power infrastructure that make the ADU ready for occupancy. Inspections are completed at required milestones throughout ADU construction.
- Interior Completion and City Sign-Off — Flooring, cabinetry, fixtures, paint are fitted and completed to your specifications. A final city inspection grants legal occupancy status and your new space is cleared for use.
Who Is a Right Fit for ADU Construction?
People who see the greatest return from ADU construction often belong to a few recognizable groups. If you are a homeowner with enough lot space to meet setback requirements, you're already well-positioned. Homeowners wanting check here to add a revenue stream through rental are among the most financially driven 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 is distinct from your family's daily life. Real estate-minded homeowners who are building a portfolio are also a natural fit for ADU construction, since rental income frequently offsets build costs.
Homeowners who may want to pause and evaluate include sites with unusual utility access challenges. Parcels in historic districts or HOA-restricted communities may need a modified approach. Brother & Brother Builders reviews each property individually and honestly to recommend the right path forward.
ADU Construction FAQ
How long does ADU construction generally take from start to finish?
The total process 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 two to four months in San Jose, so starting early is important. 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?
Budget requirements differ based on project complexity and finishes selected. For most projects in this region, ADU construction generally falls between $150,000 to $400,000 or more for a detached new build. Garage conversions are generally priced lower, sometimes in the $80,000 to $150,000 range. An accurate budget can only be developed after a full site assessment.
Is ADU construction disruptive while it's underway?
The day-to-day impact depends on the project's location on your property. New construction in the rear yard are generally the least intrusive, since work happens away from the main house. Interior conversions may involve some shared wall work during certain phases of construction. Brother & Brother Builders keeps you informed about upcoming work and timelines.
Do I need to leave my home during ADU construction?
Generally speaking, you do not need to vacate your house during ADU construction. Most job sites are structured to allow you stay in your primary unit throughout the construction timeline. There are edge cases if interior conversion work touches shared systems in ways that temporarily impact livability. Our project managers will flag these situations during the pre-construction consultation.
How long will an ADU built through professional ADU construction hold up?
A well-built ADU can be expected to last as long as the main residence — typically 50 years or more. Durability depends to the systems installed, how consistently minor repairs are addressed, and how proactively issues are resolved over time. 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 diverse mix of property types that are perfectly suited for ADU construction. Residents in the Rose Garden district have found their lots accommodate detached backyard units nicely. 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.
Local regulatory bodies in this area follows defined procedures for ADU construction that experienced builders know well. Access to infrastructure along thoroughfares like Monterey Road can influence utility connection requirements for a given ADU project. Our familiarity with the San Jose permitting environment means fewer surprises from kickoff through certificate of occupancy.
Schedule Your ADU Construction Assessment Today
When you want to add an ADU to your property, Brother & Brother Builders is ready to guide you. Our experts offer licensed expertise in ADU construction for many different project types — from small attached additions to multi-room backyard residences. The process begins with a detailed, no-pressure consultation where we listen to your goals and provide an honest assessment of what's achievable.
Reach out to our team to set up your consultation. Whether you're in the early stages of planning, we enjoy walk through your options, review completed projects and give you the clarity you need to move forward. 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