Transform Your Property with Expert ADU Construction
Families in San Jose, CA are discovering that adding an accessory dwelling unit is one of the smartest investments they can make. ADU construction provides a powerful new living space on your existing property — whether you want to generate rental income. Brother & Brother Builders has helped hundreds of local homeowners see these visions to life with skill and care.
The popularity of ADU construction has grown rapidly in recent years, and it's easy to understand why. California state law now makes it easier for homeowners to build these secondary units, and local municipalities like San Jose have embraced 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 provides increased control over how your property serves your household.
At Brother & Brother Builders, we draw on extensive hands-on experience to every ADU construction build. 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 look like on your property, this guide covers everything you need to know.
What Is the ADU Construction Process?
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 — equipped with a kitchen, bathroom, sleeping area, and its own entryway — 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 below-grade dwelling units.
Mechanically, everything kicks off with a comprehensive review of your lot, where our builders evaluate lot dimensions, existing structures, soil conditions, and local code requirements. From there, blueprints are prepared and submitted to the city for permit approval. Once the paperwork is cleared, ADU construction moves into the physical build phase — which covers everything from foundational work, framing, mechanical systems, weatherproofing, and interior finishing. The result is a fully functional 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 complement the existing structure. Systems like HVAC and drainage must be designed to handle full-time occupancy. Brother & Brother Builders treats each project with the same technical discipline we bring to full 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.
- Rental Income Potential — 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 offers family members a comfortable home of their own without moving to another neighborhood.
- Customization Options — From modern studio layouts, ADU construction may be customized to your household's priorities.
- Streamlined Approval Process — Recent state legislation has minimized the barriers and delays associated with ADU construction, creating a path that is faster and less expensive than ever before.
- Efficient Use of Your Lot — Building an ADU works within your current footprint instead of consuming open land, which supports broader sustainability goals.
- Independent Living Areas — Unlike a bedroom addition, ADU construction creates a truly separate unit where occupants have full privacy.
- Durable Return on Investment — A well-built ADU remains an asset for many years and generates both functional space and financial upside.
The ADU Construction Procedure Step by Step
- Initial Property Assessment and Feasibility Review — Our experts review your property to analyze zoning rules, slope conditions, and available square footage. This step tells you exactly what's possible before any time is invested in drawings.
- Blueprint Development and Layout Design — Our design team create comprehensive blueprints reflecting your priorities. Space is thoughtfully allocated to optimize daily use.
- Permitting and City Approval — ADU construction in San Jose demands documentation to the city's building department for review and approval. We manage this entire process on your behalf, resolving any revision requests promptly.
- Ground Prep and Structural Base — Once permits are granted, the build starts. This involves leveling and prepping the ground, laying the structural base, and running initial plumbing and electrical conduits.
- Structural Framing and Weatherproofing — Framing is completed followed by roofing, siding, windows, and exterior doors. During this step, the ADU transforms from a concept to a building.
- MEP Systems Rough-In — Certified technicians install the plumbing lines, electrical wiring, and HVAC systems that make the ADU ready for occupancy. All work is inspected at designated stages throughout ADU construction.
- Finishes, Fixtures, and Final Walkthrough — Countertops, hardware, finishes, and fixtures 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?
Property owners who are best suited from ADU construction often belong to a few common profiles. If you own a single-family home with a backyard, garage, or basement that could be converted, you're already in a good starting place. Homeowners looking to generate income through rental are among the most financially driven ADU construction clients, along with families supporting elderly parents.
ADU construction also suits someone who needs a dedicated professional workspace and wants a separate office or studio space that doesn't interfere with your family's daily life. Landlords and real estate investors 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 lots that are below minimum size thresholds. Sites with underground infrastructure conflicts may face additional constraints. Brother & Brother Builders reviews each property case by case to recommend the right path forward.
ADU Construction FAQ
How long does ADU construction typically take from start to finish?
The full timeline for ADU construction commonly spans six to fourteen months, influenced by the type of unit being built and how quickly approvals come through. City review on its own can take several months in San Jose, so beginning the process sooner rather than later is wise. Simpler garage conversions can move faster, while custom detached builds take longer to complete.
What does ADU construction typically cost?
Pricing depends on many factors based on the type and size of the ADU. For most projects in this region, ADU construction typically ranges from $150,000 to $400,000 or more for a standalone backyard unit. Attached ADU additions often come in under, sometimes between $75,000 and $140,000. An accurate budget can only be produced following a formal feasibility evaluation.
Is ADU construction difficult to live through 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 the crew operates at a distance from your living areas. Garage conversions or attached additions may require temporary access during certain phases of construction. We provide advance notice about what to expect at each stage.
Do I need to move out during ADU construction?
In most cases, you are not required to vacate your primary residence during ADU construction. Most job sites are set up to let you continue living in the home throughout the process. Exceptions may arise if significant structural connections require temporary shutoffs in ways that require short-term access disruption. 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 remain in good condition?
An ADU constructed with quality materials is designed to last as long as the main residence — indefinitely with proper upkeep. Durability depends to the standard of construction, how consistently minor repairs are addressed, and whether systems like roofing and plumbing are serviced regularly. Our builds use commercial-grade materials and follow all code requirements to deliver a structure that stands the test of time.
ADU Construction for San Jose Homeowners
Residential areas across San Jose present a variety of property types that are ideally positioned for ADU construction. Property owners near the Almaden Valley area often discover their properties accommodate detached backyard units nicely. Communities around the Capitol Expressway corridor are increasingly popular for ADU construction as multigenerational living becomes more common. From neighborhoods near the Guadalupe River Park corridor to those near Branham Lane, our team knows the permitting landscape well.
The City of San Jose's building department 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 more accurate timelines and budgets from design through the final walkthrough.
Schedule Your ADU Construction Planning Session Today
When you want to move forward with ADU get more info construction, Brother & Brother Builders is here to help. Our experts offer licensed expertise in ADU construction for many different 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 provide an honest assessment of what's achievable.
Get in touch with our office to begin the conversation. Whether you're in the early stages of planning, we enjoy answer questions, share examples of our work and make sure you feel confident before committing. 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