Brother & Brother Builders

Transform Your Property with Quality ADU Construction

Homeowners across San Jose, CA are realizing that adding an accessory dwelling unit is one of the smartest investments they can make. ADU construction provides a flexible new living space on your existing property — whether you want to house a family member. Brother & Brother Builders has guided hundreds of local homeowners bring these projects to life with craftsmanship and care.

The popularity of ADU construction has increased significantly in recent years, and it's not hard to see why. California state law now makes it easier for homeowners to build these secondary units, and local municipalities like San Jose have encouraged the trend as a way to expand the housing supply. If you're planning a detached backyard cottage, a garage conversion, or an attached addition, ADU construction provides increased control over how your property works.

At Brother & Brother Builders, we apply deep hands-on experience to every ADU construction build. Our team knows the San Jose building codes, the engineering requirements, and the aesthetic decisions that make an ADU functional. When you're ready to explore what ADU construction could mean for your property, this guide covers everything you need to know.

What Is ADU Construction?

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 fully independent living space — featuring a kitchen, bathroom, sleeping area, and its own entrance — that exists on the same lot as a primary residence. ADU construction can take several forms, including detached backyard units, attached additions, garage conversions, and even basement or interior conversions.

Mechanically, the process begins with a comprehensive review of your lot, where our builders evaluate setbacks, zoning, utility access, and structural feasibility. 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 encompasses site preparation, framing, roofing, plumbing, electrical, insulation. The result is a fully functional 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 complement the existing structure. Systems like wiring and water supply must be designed to handle full-time occupancy. Brother & Brother Builders treats each project with the same high standards we apply to large-scale custom home projects.

Key Advantages 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.
• 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 gives aging parents a comfortable home of their own without losing proximity to the family.
• Personalized Layouts — From open-plan one-bedrooms, ADU construction can be tailored to the intended occupant's lifestyle.
• Streamlined Approval Process — Recent state legislation has reduced the red tape associated with ADU construction, creating a path that is faster and more cost-efficient than ever before.
• Sustainable Land Use — Building an ADU works within your current footprint instead of consuming open land, which supports broader sustainability goals.
• Separate Entrances and Spaces — Unlike a bedroom addition, ADU construction produces a fully self-contained unit where occupants have full privacy.
• Durable Return on Investment — A well-built ADU holds its value for the long haul by offering both functional space and financial upside.

The ADU Construction Procedure Step by Step

1. Property Walkthrough and Feasibility Check — Our experts review your property to determine what type of ADU is allowed and where it can be placed. This phase answers exactly what can be built before any time is invested in drawings.
2. Custom Design and Architectural Planning — Licensed architects and designers create detailed floor plans reflecting your priorities. Space is thoughtfully allocated to create practical, comfortable living.
3. Permitting and City Approval — ADU construction in San Jose demands documentation to the city's building department for sign-off and verification. Brother & Brother Builders coordinates the permitting on your behalf, responding to review feedback promptly.
4. Site Preparation and Foundation Work — Once permits are approved, physical construction begins. This involves leveling and prepping the ground, laying the structural base, and running initial plumbing and electrical conduits.
5. Framing, Roofing, and Exterior Work — Framing is completed followed by weatherproofing and exterior finish materials. At this stage, the ADU takes its visible shape.
6. Mechanical, Electrical, and Plumbing Installation — Certified technicians install the water supply, drain lines, and electrical panel that make the ADU operationally complete. Every system is reviewed at each code checkpoint throughout ADU construction.
7. Interior Finishing and Final Inspections — Flooring, cabinetry, fixtures, paint are fitted and completed to the approved plan. A final city inspection grants legal occupancy status and the unit is officially approved for use.

Who Is a Good Candidate 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 a strong candidate. Homeowners wanting to add a revenue stream through rental are among the most common 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 remains away from your family's daily life. Real estate-minded homeowners who want to maximize their land are also well suited for ADU construction, since the long-term value is proven.

Those who should discuss alternatives first include properties with significant setback limitations. Sites with underground infrastructure conflicts may face additional constraints. Our experts will evaluate each property on its own merits to advise you on what's feasible.

ADU Construction Common Questions Answered

How long does ADU construction typically take from start to finish?

The full timeline for ADU construction usually runs between six to fourteen months, influenced by the type of unit being built and local permitting timelines. City review on its own can take a significant portion of the overall timeline in San Jose, so beginning the process sooner rather than later is wise. Straightforward interior 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 usually run in terms of budget?

Budget requirements differ based on whether it's a conversion or new construction. In the San Jose area, 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 given after completing 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. Standalone ADU projects 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 specific stages like framing or MEP rough-in. Brother & Brother Builders keeps you informed about what to expect at each stage.

Do I need to vacate the property during ADU construction?

Generally speaking, you are not required to vacate your house during ADU construction. Most job sites are designed so that you stay in your primary unit throughout the build. Exceptions may arise if interior conversion work touches shared systems in ways that require short-term access disruption. Our project managers 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?

A well-built ADU is designed to last as long as any standard residential structure — often several decades with routine maintenance. How long it lasts comes down to the standard of construction, how consistently minor repairs are addressed, and if mechanical components are maintained on schedule. Brother & Brother Builders specifies high-quality components and comply with all local building codes to deliver a structure that stands the test of time.

ADU Construction for San Jose Homeowners

San Jose's neighborhoods offer a wide range of property types that are ideally positioned for ADU construction. Homeowners in the Willow Glen neighborhood frequently see their parcels work well for both attached and detached projects. The Berryessa area have seen growing ADU activity as families expand. If you're located closer to Evergreen, our team has likely worked nearby.

The City of San Jose's building department applies particular standards for ADU construction that require a builder familiar with local expectations. Access to infrastructure along thoroughfares like Monterey Road can affect how quickly permits are approved for a given ADU project. Brother & Brother Builders' experience across the San Jose permitting environment means fewer surprises from design through the final walkthrough.

Book Your ADU Construction Planning Session Today

If you're ready to add an ADU to your property, Brother & Brother Builders is the team to call. We bring years of hands-on experience in ADU construction across a wide range of project types — from modest studio builds to large custom detached cottages. Every project starts with a detailed, no-pressure consultation where we learn what you're trying to accomplish and provide an honest assessment of what's achievable.

Get in touch with our office to adu construction CA set up your consultation. Whether you're in the early stages of planning, we enjoy walk through your options, review completed projects and make sure you feel confident before committing. This type of project is a meaningful commitment — and we're committed to helping you get it right.

Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632