Unlock New Space with Quality ADU Construction
Families in San Jose, CA are finding that adding an accessory dwelling unit is one of the most rewarding investments they can make. ADU construction provides a powerful new living get more info space on your existing property — whether you want to house a family member. Brother & Brother Builders has supported hundreds of local homeowners turn these plans to life with craftsmanship and care.
The interest in ADU construction has grown rapidly in recent years, and it's easy to understand why. California state law has simplified the process for homeowners to construct these secondary units, and local municipalities like San Jose have supported the trend as a way to expand the housing supply. Whether you want to build 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 job. Our team knows the San Jose building codes, the engineering details, and the design choices that make an ADU functional. When you're ready to explore what ADU construction could look like on your property, this guide will walk you through everything you need to know.
What Is the ADU Construction Process?
ADU construction involves the process of planning, approving, and constructing 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 entryway — that sits on the same property as a primary residence. ADU construction includes various structural types, including detached backyard units, attached additions, garage conversions, and even interior space reconfigurations.
Mechanically, everything kicks off with a thorough property evaluation, where our builders evaluate property boundaries, available square footage, and infrastructure capacity. From there, design plans are prepared and submitted to the local building department. Once approvals are in place, ADU construction transitions to the physical build phase — which encompasses site preparation, framing, HVAC, drywall, flooring, and exterior finishes. The result is a move-in-ready living unit attached to or separate from your main home.
The difference between a good and a great ADU build is the level of craftsmanship at every stage. Materials must be selected to match the primary home's aesthetic. Systems like plumbing and electrical must be built for long-term residential demand. Brother & Brother Builders approaches every build with the same technical discipline we bring to full custom home projects.
Key Benefits ADU Construction
- Boosted Home Equity — ADU construction delivers real 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, creating ongoing passive income for the homeowner.
- Multi-Generational Living — ADU construction provides adult children a self-contained residence without moving to another neighborhood.
- Customization Options — From open-plan one-bedrooms, ADU construction can be tailored to the intended occupant's lifestyle.
- Streamlined Approval Process — Recent state legislation has cut down the barriers and delays associated with ADU construction, resulting in a timeline that is faster and less expensive than ever before.
- Sustainable Land Use — Building an ADU uses your existing lot instead of consuming open land, which aligns with sustainability goals.
- Separate Entrances and Spaces — Unlike a bedroom addition, ADU construction produces a fully self-contained unit where tenants live autonomously.
- Long-Term Investment Security — A well-built ADU holds its value for the long haul by offering both functional space and financial upside.
The ADU Construction Journey Step by Step
- Initial Property Assessment and Feasibility Review — Our team visits your property to evaluate setbacks, lot coverage limits, and utility connections. This step tells you exactly what ADU types will work before any resources go toward planning.
- Custom Design and Architectural Planning — Licensed architects and designers create precise architectural drawings tailored to your needs. Layouts are carefully considered to optimize daily use.
- Permitting and City Approval — ADU construction in San Jose demands documentation to the city's building department for sign-off and verification. Our team handles all submissions on your behalf, addressing any city comments promptly.
- Excavation and Foundation Installation — Once permits are approved, physical construction begins. This includes grading the site, pouring the concrete foundation, and running initial plumbing and electrical conduits.
- Framing, Roofing, and Exterior Work — The structural frame is erected followed by roofing, siding, windows, and exterior doors. During this step, the ADU becomes recognizable as a structure.
- Mechanical, Electrical, and Plumbing Installation — Licensed subcontractors install the plumbing lines, electrical wiring, and HVAC systems that make the ADU ready for occupancy. Inspections are completed at required milestones throughout ADU construction.
- Interior Completion and City Sign-Off — Countertops, hardware, finishes, and fixtures are placed and inspected to the approved plan. A last official inspection issues the certificate of occupancy and your new space is cleared for use.
Who Is a Strong Candidate for ADU Construction?
Homeowners who benefit most from ADU construction generally fit within a few recognizable groups. If you have a residential property with enough lot space to meet setback requirements, you're already well-positioned. Homeowners wanting to add a revenue stream through rental are among the most motivated ADU construction clients, along with families supporting elderly parents.
ADU construction also suits someone who runs a small business and wants a private work environment that is distinct from your family's daily life. Property investors and rental owners who are building a portfolio are also a natural fit 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. Sites with underground infrastructure conflicts may need a modified approach. Our experts will evaluate each property individually and honestly to provide realistic options.
ADU Construction Common Questions Answered
How long does ADU construction typically take from start to finish?
The full timeline 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 beginning the process sooner rather than later is wise. Smaller detached units often finish in the lower end of the range, while custom detached builds require more time.
What does ADU construction cost in San Jose?
Pricing depends on many factors based on the type and size of the ADU. For most projects in this region, ADU construction commonly costs $150,000 to $400,000 or more for a fully custom construction. Attached ADU additions tend to cost less, sometimes in the $80,000 to $150,000 range. A precise cost projection can only be produced following a thorough property review.
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. Standalone ADU projects are typically less disruptive, since the construction zone is separate. Projects that connect to the main structure may involve some shared wall work during certain phases of construction. We provide advance notice about any phases that may affect your routine.
Do I need to move out during ADU construction?
In most cases, you do not need to vacate your main home during ADU construction. The vast majority of projects are set up to let you stay in your primary unit throughout the process. There are edge cases if significant structural connections require temporary shutoffs in ways that require short-term access disruption. Our project managers will walk you through any potential disruptions during the kickoff meeting.
How long will an ADU built through professional ADU construction remain in good condition?
An ADU constructed with quality materials can be expected to last as long as any standard residential structure — indefinitely with proper upkeep. How long it lasts comes down to the systems installed, how well routine maintenance is performed, and if mechanical components are maintained on schedule. Our builds use commercial-grade materials and follow all code requirements to protect your investment for the long haul.
ADU Construction for San Jose Homeowners
The communities throughout San Jose provide a variety of property types that are ideally positioned for ADU construction. Homeowners in the Willow Glen neighborhood frequently see their parcels are well configured for ADU builds. The Berryessa area have seen growing ADU activity as housing demand rises. Whether your property is near downtown San Jose, our team knows the permitting landscape well.
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 affect how quickly permits are approved for a given ADU project. Our familiarity with this region's building landscape means smoother project delivery from kickoff through certificate of occupancy.
Schedule Your ADU Construction Consultation Today
When you want to move forward with ADU construction, Brother & Brother Builders is the team to call. Our builders provide years of hands-on experience in ADU construction across a wide range of project types — from simple garage conversions to multi-room backyard residences. Every project starts with a thorough and honest property review where we understand your vision and give you a realistic picture of what's achievable.
Reach out to our team to schedule a site visit. Even if you're just exploring the idea, we enjoy walk through your options, review completed projects and make sure you feel confident before committing. ADU construction is a significant investment — and our goal is to ensure it delivers real value.
Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632