Unlock New Space with Professional ADU Construction
Property owners throughout San Jose, CA are realizing that adding an accessory dwelling unit is one of the smartest investments they can make. ADU construction creates a versatile 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 precision and integrity.
The popularity of 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 build these secondary units, and local municipalities like San Jose have supported the trend as a way to address housing needs. 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 job. Our team is familiar with city and county requirements, the engineering requirements, and the design choices that make an ADU truly livable. Should you want to learn about what ADU construction could do for your property, this guide explains everything you need to know.
What Is an ADU Build?
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 fully independent living space — featuring a kitchen, bathroom, sleeping area, and its own entryway — that sits on the same property 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 process begins with a thorough property evaluation, where our professionals evaluate property boundaries, available square footage, and infrastructure capacity. From there, architectural drawings are prepared and submitted to the relevant municipal authority. Once the paperwork is cleared, ADU construction transitions to the physical build phase — which covers everything from foundational work, framing, HVAC, drywall, flooring, and exterior finishes. The result is a move-in-ready living unit connected to or independent of your main home.
What separates excellent ADU construction from adu construction CA an average project is the depth of planning at every stage. Components should be specified to align with the neighborhood's character. 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
- Boosted Home Equity — ADU construction adds measurable market value to your property, often returning more than the build cost when it's time to sell.
- Revenue Generation — A completed ADU can be rented as a long-term rental or short-term vacation unit, generating steady monthly revenue for the homeowner.
- Multi-Generational Living — ADU construction offers family members a self-contained residence without leaving the property.
- Personalized Layouts — From modern studio layouts, ADU construction may be customized to your household's priorities.
- Faster Permitting in California — Recent state legislation has cut down the red tape associated with ADU construction, creating a path that is faster and less expensive than ever before.
- Responsible Property Development — Building an ADU works within your current footprint instead of consuming open land, which contributes to sustainability goals.
- Independent Living Areas — Unlike a bedroom addition, ADU construction produces a fully self-contained unit where residents have their own space.
- Durable Return on Investment — A well-built ADU continues to produce returns for many years and generates both livable square footage and monetary benefit.
The ADU Construction Procedure Step by Step
- Initial Property Assessment and Feasibility Review — Our builders assess your property to evaluate setbacks, lot coverage limits, and utility connections. This phase answers exactly what can be built before any money is spent on design.
- Custom Design and Architectural Planning — Our design team create comprehensive blueprints reflecting your priorities. Every square foot is planned to create practical, comfortable living.
- Permit Submission and Municipal Review — ADU construction in San Jose requires submitting plans to the city's building department for review and approval. Brother & Brother Builders coordinates the permitting on your behalf, resolving any revision requests promptly.
- Site Preparation and Foundation Work — Once permits are issued, on-site work kicks off. This covers land preparation, pouring the concrete foundation, and setting up utilities.
- Structural Framing and Weatherproofing — Walls and roof systems go up followed by insulation, sheathing, and exterior cladding. This phase, 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 ready for occupancy. Inspections are completed at designated stages throughout ADU construction.
- Interior Completion and City Sign-Off — Trim, appliances, tile, and lighting are installed and finished to your specifications. A final city inspection confirms the unit is code-compliant and the ADU is ready for use.
Who Is a Strong Candidate for ADU Construction?
People who see the greatest return from ADU construction often belong to a few recognizable groups. If you own a single-family home with enough lot space to meet setback requirements, 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.
You may also be someone who works from home and wants a detached creative or business space that remains away from your family's daily life. Property investors and rental owners who already own residential properties are also a natural fit for ADU construction, since rental income frequently offsets build costs.
Those who should discuss alternatives first include lots that are below minimum size thresholds. Very small lots or properties with easements may need a modified approach. Our experts will evaluate each property individually and honestly to recommend the right path forward.
ADU Construction Common Questions Answered
How long does ADU construction usually take from start to finish?
The total process for ADU construction commonly spans 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 beginning the process sooner rather than later is wise. Simpler garage conversions may complete more quickly, while larger new construction ADUs require more time.
What does ADU construction typically cost?
Pricing depends on many factors based on project complexity and finishes selected. In the San Jose area, ADU construction generally falls between $150,000 to $400,000 or more for a fully custom construction. Garage conversions tend to cost less, sometimes starting around $80,000 depending on scope. A detailed estimate can only be developed after a thorough property review.
Is ADU construction intrusive while it's underway?
The level of disruption depends on the project's location on your property. Detached backyard builds are usually easier to live alongside, since the crew operates at a distance from your living areas. Projects that connect to the main structure may create short-term inconveniences during specific stages like framing or MEP rough-in. We provide advance notice about upcoming work and timelines.
Do I need to move out during ADU construction?
For the majority of homeowners, you do not need to vacate your house during ADU construction. Most builds are set up to let you continue living in the home throughout the build. Exceptions may arise if major utility upgrades affect the main house in ways that temporarily impact livability. Our construction supervisors will discuss these scenarios during the kickoff meeting.
How long will an ADU built through professional ADU construction remain in good condition?
A well-built ADU is designed to last as long as your primary home — often several decades with routine maintenance. Longevity is tied to the systems installed, how well routine maintenance is performed, and how proactively issues are resolved over time. Our builds use residential-grade products rated for longevity and build to current California residential standards to deliver a structure that stands the test of time.
ADU Construction for Local 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 often discover their properties work well for both attached and detached projects. Communities around the Capitol Expressway corridor have seen growing ADU activity as housing demand rises. 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 applies particular standards for ADU construction that experienced builders know well. Access to infrastructure along thoroughfares like Monterey Road can impact the design approach for a given ADU project. Our familiarity with these local conditions means more accurate timelines and budgets from kickoff through certificate of occupancy.
Start Your ADU Construction Consultation Today
Should you be thinking about how to move forward with ADU construction, Brother & Brother Builders is here to help. Our builders provide years of hands-on experience in ADU construction for many different project types — from simple garage conversions to large custom detached cottages. Our approach opens with a detailed, no-pressure consultation where we understand your vision and give you a realistic picture of what ADU construction on your property will look like.
Get in touch with our office to set up your consultation. Whether you're in the early stages of planning, we're glad to answer questions, share examples of our work and make sure you feel confident before committing. Building an ADU is a major decision — and our goal is to ensure it delivers real value.
Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632