Unlock New Space with Professional ADU Construction
Property owners throughout San Jose, CA are finding that adding an accessory dwelling unit is one of the most practical investments they can make. ADU construction provides a versatile new living space on your existing property — whether you want to generate rental income. Brother & Brother Builders has supported hundreds of local homeowners bring these projects to life with skill and care.
The popularity of ADU construction has increased significantly in recent years, and it's no mystery. California state law now makes it easier for homeowners to build these secondary units, and local municipalities like San Jose have supported 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 offers greater control over how your property functions.
At Brother & Brother Builders, we bring years of hands-on experience to every ADU construction build. Our team understands the local permitting process, the engineering details, and the aesthetic decisions that make an ADU beautiful. Should you want to learn about what ADU construction could mean for your property, this guide will walk you through everything you need to know.
What Is the ADU Construction Process?
ADU construction describes the process of planning, approving, and constructing an accessory dwelling unit on a residential property. An accessory dwelling unit is a self-contained living space — featuring a kitchen, bathroom, sleeping area, and its own entrance — that exists on the same lot as a primary residence. ADU construction includes various structural types, including detached backyard units, attached additions, garage conversions, and even below-grade dwelling units.
Mechanically, everything kicks off with a detailed site assessment, where our team 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 permits are secured, ADU construction transitions to the physical build phase — which encompasses site preparation, framing, mechanical systems, weatherproofing, and interior finishing. The result is a completely finished living unit adjacent to or detached from 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 complement the existing structure. Systems like HVAC and drainage 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 Benefits ADU Construction
- Boosted Home Equity — 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, providing a consistent income stream for the homeowner.
- Housing for Extended Family — ADU construction provides adult children a private, independent living space without losing proximity to the family.
- Personalized Layouts — From two-bedroom configurations, ADU construction can be tailored to your specific needs.
- Faster Permitting in California — Recent state legislation has cut down the red tape associated with ADU construction, creating a path that is faster and more cost-efficient than ever before.
- Responsible Property Development — Building an ADU maximizes the land you already own instead of expanding urban sprawl, which aligns with sustainability goals.
- Separate Entrances and Spaces — Unlike a bedroom addition, ADU construction produces a fully self-contained unit where occupants have full privacy.
- Lasting Financial Benefit — A well-built ADU remains an asset for the long haul by offering both livable square footage and monetary benefit.
The ADU Construction Journey Step by Step
- Initial Property Assessment and Feasibility Review — Our experts review your property to evaluate setbacks, lot coverage limits, and utility connections. This stage clarifies exactly what's possible before any time is invested in drawings.
- Custom Design and Architectural Planning — Our design team create detailed floor plans reflecting your priorities. Every square foot is planned to create practical, comfortable living.
- Permit Submission and Municipal Review — ADU construction in San Jose involves filing drawings to the city's building department for review and approval. We manage this entire process on your behalf, addressing any city comments promptly.
- Excavation and Foundation Installation — Once permits are granted, on-site work kicks off. This includes grading the site, laying the structural base, and establishing utility connections.
- Shell Construction and Exterior Finishing — Walls and roof systems go up followed by roofing, siding, windows, and exterior doors. At this stage, the ADU takes its visible shape.
- MEP Systems Rough-In — Certified technicians install the heating, cooling, drainage, and power infrastructure that make the ADU ready for occupancy. All work is inspected at required milestones throughout ADU construction.
- Interior Completion and City Sign-Off — Trim, appliances, tile, and lighting are fitted and completed to the agreed design. A final city inspection grants legal occupancy status and your new space is cleared for use.
Who Is a Good 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 available square footage under zoning rules, you're already a strong candidate. Homeowners looking to generate income through rental are among the most common ADU construction clients, along with families accommodating adult children who need housing.
ADU construction also suits someone who runs a small business and wants a detached creative or business space that remains away from your family's daily life. Landlords and real estate investors who want to maximize their land are also well suited for ADU construction, since the return on investment is well-documented.
Situations where ADU construction may not be the best first step include properties with significant setback limitations. Parcels in historic districts or HOA-restricted communities may require additional review. Brother & Brother Builders reviews each property individually and honestly to advise you on what's feasible.
ADU Construction Common Questions Answered
How long does ADU construction typically take from start to finish?
The complete duration for ADU construction typically ranges from six to fourteen months, depending on design complexity and city review schedules. City review on its own can take several months in San Jose, so starting early is important. Smaller detached units may complete more quickly, while multi-room detached cottages require more time.
What does ADU construction cost in San Jose?
Budget requirements differ based on project complexity and finishes selected. In the San Jose area, ADU construction commonly costs $150,000 to $400,000 or more for a detached new build. Interior conversion projects tend to cost less, sometimes in the $80,000 to $150,000 range. A detailed estimate 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. Detached backyard builds are generally the least intrusive, since work happens away from the main house. Garage conversions or attached additions may require temporary access during specific stages like framing or MEP rough-in. Brother & Brother Builders keeps you informed about any phases that may affect your routine.
Do I need to move out during ADU construction?
Generally speaking, you do not need to vacate your main home during ADU construction. Most builds are set up to let you remain on the property throughout the process. Exceptions may arise if major utility upgrades affect the main house in ways that temporarily impact livability. The team at Brother & Brother Builders will flag these situations during the kickoff meeting.
How long will an ADU built through professional ADU construction hold up?
A well-built ADU should last as long as the main residence — often several decades with routine maintenance. How long it lasts comes down to the quality of materials used, how consistently minor repairs are addressed, and how proactively issues are resolved over time. Our builds use residential-grade products rated for longevity and follow all code requirements to deliver a structure that stands the test of time.
ADU Construction for San Jose Homeowners
The communities throughout San Jose provide a variety of property types that are well suited for ADU construction. Homeowners in the Willow Glen neighborhood frequently see their parcels work well for both attached and detached projects. Communities around the Capitol Expressway corridor are seeing more homeowners add secondary units as housing demand rises. From neighborhoods near the Guadalupe River Park corridor to those near Branham Lane, our team has likely worked nearby.
Local regulatory bodies in this area applies particular standards for ADU construction that require a builder familiar with local expectations. Access to infrastructure along thoroughfares like Monterey Road can influence utility connection requirements for a given ADU project. Our team's knowledge of this region's building landscape read more means more accurate timelines and budgets from design through the final walkthrough.
Start Your ADU Construction Assessment Today
When you want to move forward with ADU construction, Brother & Brother Builders is the team to call. Our experts offer licensed expertise in ADU construction including all types of project types — from small attached additions to fully independent secondary homes. Our approach opens with a thorough and honest property review where we listen to your goals and give you a realistic picture of what ADU construction on your property will look like.
Contact Brother & Brother Builders to begin the conversation. No matter where you are in the decision-making process, our team is happy to answer questions, share examples of our work and give you the clarity you need to move forward. 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