Transform Your Property with Quality ADU Construction
Property owners throughout San Jose, CA are realizing that adding an accessory dwelling unit is one of the most rewarding investments they can make. ADU construction provides a flexible 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 care.
The demand for ADU construction has increased significantly in recent years, and it's easy to understand why. California state law has streamlined permitting for homeowners to add 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 functions.
At Brother & Brother Builders, we apply deep hands-on experience to every ADU construction project. Our team is familiar with city and county requirements, the engineering requirements, and the design choices that make an ADU truly livable. When you're ready to explore what ADU construction could look like on your property, this guide covers everything you need to know.
What Is ADU Construction?
ADU construction involves the process of designing, permitting, and building an accessory dwelling unit on a residential property. An accessory dwelling unit is a self-contained living space — equipped with a kitchen, bathroom, sleeping area, and its own access point — 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 work starts with a detailed site assessment, where our professionals evaluate property boundaries, available square footage, and infrastructure capacity. From there, blueprints are prepared and submitted to the relevant municipal authority. Once permits are secured, ADU construction transitions to the physical build phase — which covers everything from foundational work, framing, mechanical systems, weatherproofing, and interior finishing. The result is a move-in-ready 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 plumbing and electrical must be built for long-term residential demand. Brother & Brother Builders approaches every build with the same high standards 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 generating strong equity gains when it's time to sell.
- Revenue Generation — A completed ADU may be listed 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 comfortable home of their own without losing proximity to the family.
- Personalized Layouts — From modern studio layouts, ADU construction may be customized to your household's priorities.
- Streamlined Approval Process — Recent state legislation has minimized the red tape associated with ADU construction, making the process that is faster and less expensive than ever before.
- Efficient Use of Your Lot — 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 creates a truly separate unit where occupants have full privacy.
- Lasting Financial Benefit — A well-built ADU holds its value for many years and generates both livable square footage and monetary benefit.
The ADU Construction Journey Step by Step
- Property Walkthrough and Feasibility Check — Our experts review your property to analyze zoning rules, slope conditions, and available square footage. This phase answers 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. Space is thoughtfully allocated to maximize function and livability.
- Permitting and City Approval — ADU construction in San Jose involves filing drawings to the city's building department for sign-off and verification. We manage this entire process on your behalf, addressing any city comments promptly.
- Excavation and Foundation Installation — Once permits are approved, physical construction begins. This involves leveling and prepping the ground, 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. During this step, the ADU becomes recognizable as a structure.
- 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.
- Finishes, Fixtures, and Final Walkthrough — Flooring, cabinetry, fixtures, paint are placed and inspected to the agreed design. A closing municipal review issues the certificate of occupancy and the ADU is ready for use.
Who Is a Right Fit for ADU Construction?
People who see the greatest return from ADU construction often belong to a few recognizable groups. If you have a residential property with a backyard, garage, or basement that could be converted, you're already in a good starting place. Homeowners wanting to add a revenue stream through rental are among the most financially driven ADU construction clients, along with families supporting elderly parents.
Another strong candidate is someone who works from home and wants a private work environment that doesn't interfere with your family's daily life. Property investors and rental owners who want to maximize their land are also well suited for ADU construction, since the long-term value is proven.
Homeowners who may want to pause and evaluate include lots that are below minimum size thresholds. Sites with underground infrastructure conflicts may need a modified approach. Brother & Brother Builders reviews each property on its own merits to advise you on what's feasible.
ADU Construction FAQ
How long does ADU construction generally take from start to finish?
The complete duration for ADU construction usually runs between six to fourteen months, based on the project scope and local permitting timelines. City review on its own can take two to four months in San Jose, so starting early is important. Simpler garage conversions often finish in the lower end of the range, while larger new construction ADUs fall toward the upper end of the timeline.
What does ADU construction typically cost?
Costs vary widely 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 standalone backyard unit. Attached ADU additions often come in under, sometimes starting around $80,000 depending on scope. A precise cost projection can only be given after completing a thorough property review.
Is ADU construction disruptive while it's underway?
The level of disruption depends on whether you're converting existing space or building new. Detached backyard builds are generally the least intrusive, since the crew operates at a distance from your living areas. Interior conversions may create short-term inconveniences during key milestones. Brother & Brother Builders keeps you informed about what to expect at each stage.
Do I need to leave my home during ADU construction?
In most cases, you do not need to vacate your house during ADU construction. The vast majority of projects are structured to allow you remain on the property throughout the construction timeline. Exceptions may arise if significant structural connections require temporary shutoffs 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 last?
Any ADU built to code with professional oversight can be expected to last as long as any standard residential structure — 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 if mechanical components are maintained on schedule. We select 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. Property owners near the Almaden Valley area have found their lots accommodate detached backyard units nicely. The Berryessa area 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 project experience in the area.
Local regulatory bodies in this area applies particular standards for ADU construction that experienced builders know well. Location near major arterials like Story Road or Tully Road can influence utility connection requirements for a given ADU project. Brother & Brother Builders' experience across this region's building landscape means fewer surprises from design through the final walkthrough.
Book Your ADU Construction Planning Session Today
Should you be thinking about how to move forward with ADU construction, Brother & Brother Builders is here to help. We bring years of hands-on experience in ADU construction across a wide range of project types — from simple garage conversions to fully independent secondary homes. Every project starts with a thorough and honest property review where we listen to your goals and provide an honest assessment of what ADU construction get more info on your property will look like.
Get in touch with our office to set up your consultation. No matter where you are in the decision-making process, our team is happy to answer questions, share examples of our work and help you take the next step. 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