Transform Your Property with Professional ADU Construction
Families in San Jose, CA are finding that adding an accessory dwelling unit is one of the smartest investments they can make. ADU construction opens the door to a flexible new living space on your existing property — whether you want to house a family member. Brother & Brother Builders has guided hundreds of local homeowners see these visions to life with craftsmanship and care.
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 add these secondary units, and local municipalities like San Jose have supported the trend as a way to increase density responsibly. Whether you want to build 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 more info draw on extensive hands-on experience to every ADU construction project. Our team knows the San Jose building codes, the engineering requirements, and the planning steps that make an ADU beautiful. If you've been thinking about what ADU construction could do for your property, this guide explains everything you need to know.
What Is an ADU Build?
ADU construction involves 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 entryway — 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 interior space reconfigurations.
Mechanically, the work starts with a thorough property evaluation, where our builders evaluate lot dimensions, existing structures, soil conditions, and local code requirements. From there, architectural drawings are prepared and submitted to the relevant municipal authority. 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 move-in-ready living unit connected to or independent of your main home.
The difference between a good and a great ADU build is the attention to detail at every stage. Products need to be chosen to match the primary home's aesthetic. Systems like HVAC and drainage must be built for long-term residential demand. Brother & Brother Builders approaches every build with the same professional rigor we bring to full custom home projects.
Key Benefits 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.
- Revenue Generation — A completed ADU can be rented as a long-term rental or short-term vacation unit, creating ongoing passive income for the homeowner.
- Space for Loved Ones — ADU construction offers family members a comfortable home of their own without losing proximity to the family.
- Design Flexibility — From two-bedroom configurations, ADU construction can be tailored to your specific needs.
- Streamlined Approval Process — Recent state legislation has minimized the permitting obstacles associated with ADU construction, making the process that is faster and more cost-efficient than ever before.
- Responsible Property Development — Building an ADU works within your current footprint instead of expanding urban sprawl, which aligns with sustainability goals.
- Privacy for All Residents — Unlike a bedroom addition, ADU construction creates a truly separate unit where occupants have full privacy.
- Durable Return on Investment — A well-built ADU continues to produce returns for decades, providing both usable housing and equity growth.
The ADU Construction Procedure Step by Step
- Property Walkthrough and Feasibility Check — Our experts review 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 resources go toward planning.
- Custom Design and Architectural Planning — Experienced draftspeople create comprehensive blueprints reflecting your priorities. Every square foot is planned to optimize daily use.
- Permit Submission and Municipal Review — ADU construction in San Jose requires submitting plans to the city's building department for sign-off and verification. Our team handles all submissions on your behalf, resolving any revision requests promptly.
- Ground Prep and Structural Base — Once permits are issued, physical construction begins. This includes grading the site, completing foundation work, and running initial plumbing and electrical conduits.
- Structural Framing and Weatherproofing — Framing is completed followed by roofing, siding, windows, and exterior doors. This phase, the ADU becomes recognizable as a structure.
- MEP Systems Rough-In — Licensed subcontractors install the plumbing lines, electrical wiring, and HVAC systems that make the ADU fully functional. Inspections are completed at required milestones throughout ADU construction.
- Interior Completion and City Sign-Off — Flooring, cabinetry, fixtures, paint are placed and inspected to your specifications. A final city inspection confirms the unit is code-compliant and the ADU is ready for use.
Who Is a Right Fit for ADU Construction?
People who see the greatest return from ADU construction typically fall into a few clear categories. If you are a homeowner 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 navigating multigenerational living situations.
Another strong candidate is someone who needs a dedicated professional workspace and wants a detached creative or business space that is distinct from your family's daily life. Property investors and rental owners who want to maximize their land are also prime candidates for ADU construction, since the long-term value is proven.
Situations where ADU construction may not be the best first step include properties with significant setback limitations. Very small lots or properties with easements may face additional constraints. Our team can assess each property on its own merits 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 usually runs between six to fourteen months, influenced by the type of unit being built and city review schedules. The approval phase alone can take several months in San Jose, so planning ahead matters. Smaller detached units often finish in the lower end of the range, while custom detached builds take longer to complete.
What does ADU construction usually run in terms of budget?
Pricing depends on many factors based on the type and size of the ADU. Locally, ADU construction generally falls between $150,000 to $400,000 or more for a standalone backyard unit. Garage conversions are generally priced lower, sometimes starting around $80,000 depending on scope. An accurate budget can only be developed after a full site assessment.
Is ADU construction intrusive while it's underway?
The day-to-day impact depends on where the ADU is being built. New construction in the rear yard are typically less disruptive, since the crew operates at a distance from your living areas. Garage conversions or attached additions may involve some shared wall work during key milestones. Brother & Brother Builders keeps you informed about what to expect at each stage.
Do I need to move out during ADU construction?
For the majority of homeowners, you won't have to vacate your primary residence during ADU construction. The vast majority of projects are set up to let you stay in your primary unit throughout the build. Certain situations could require a brief departure if major utility upgrades affect the main house in ways that briefly affect habitability. Our construction supervisors will flag these situations 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 the main residence — indefinitely with proper upkeep. How long it lasts comes down to the quality of materials used, whether the unit is properly cared for, and if mechanical components are maintained on schedule. Our builds use residential-grade products rated for longevity and comply with all local building codes to ensure lasting performance.
ADU Construction for San Jose Homeowners
The communities throughout San Jose provide a diverse mix of property types that are perfectly suited for ADU construction. Residents in the Rose Garden district have found their lots work well for both attached and detached projects. Neighborhoods near Blossom Hill Road are increasingly popular for ADU construction as families expand. From neighborhoods near the Guadalupe River Park corridor to those near Branham Lane, 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. Access to infrastructure along thoroughfares like Monterey Road can affect how quickly permits are approved for a given ADU project. Our familiarity with these local conditions means more accurate timelines and budgets from kickoff through certificate of occupancy.
Book Your ADU Construction Assessment Today
Should you be thinking about how to add an ADU to your property, Brother & Brother Builders is the team to call. We bring proven skills in ADU construction across a wide range of project types — from modest studio builds to fully independent secondary homes. The process begins with a detailed, no-pressure consultation where we listen to your goals and share clear expectations of what the project will involve.
Contact Brother & Brother Builders to schedule a site visit. Whether you're in the early stages of planning, we enjoy answer questions, share examples of our work and help you take the next step. This type of project is a meaningful commitment — and our goal is to ensure it delivers real value.
Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632