Brother & Brother Builders

Unlock New Space with Quality ADU Construction

Homeowners across San Jose, CA are discovering that adding an accessory check here dwelling unit is one of the most rewarding investments they can make. ADU construction creates a powerful new living space on your existing property — whether you want to create a private workspace. Brother & Brother Builders has supported hundreds of local homeowners bring these projects to life with precision and integrity.

The popularity of ADU construction has grown rapidly in recent years, and it's no mystery. California state law has streamlined permitting for homeowners to add these secondary units, and local municipalities like San Jose have encouraged 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 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 details, 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 an ADU Build?

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 — equipped with a kitchen, bathroom, sleeping area, and its own access point — that is located on the same parcel 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 detailed site assessment, where our builders evaluate setbacks, zoning, utility access, and structural feasibility. From there, design plans are prepared and submitted to the local building department. Once permits are secured, ADU construction moves into the physical build phase — which covers everything from foundational work, framing, HVAC, drywall, flooring, and exterior finishes. The result is a fully functional living unit attached to or separate from your main home.

What sets quality ADU construction apart is the depth of planning at every stage. Materials must be selected to complement the existing structure. Systems like plumbing and electrical must be designed to handle full-time occupancy. Brother & Brother Builders approaches every build with the same technical discipline we use on major 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 may be listed as a long-term rental or short-term vacation unit, creating ongoing passive income for the homeowner.
• Space for Loved Ones — ADU construction gives aging parents a private, independent living space without leaving the property.
• Personalized Layouts — From modern studio layouts, ADU construction may be customized to your household's priorities.
• Streamlined Approval Process — Recent state legislation has cut down the red tape associated with ADU construction, creating a path that is faster and more affordable than ever before.
• Efficient Use of Your Lot — Building an ADU works within your current footprint instead of requiring new development, which contributes to sustainability goals.
• Independent Living Areas — 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 decades, providing both functional space and financial upside.

The ADU Construction Procedure Step by Step

1. Property Walkthrough and Feasibility Check — Our team visits your property to analyze zoning rules, slope conditions, and available square footage. This phase answers exactly what ADU types will work before any time is invested in drawings.
2. Architectural Drafting and Space Planning — Licensed architects and designers create detailed floor plans based on your goals. Every square foot is planned to optimize daily use.
3. 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, responding to review feedback promptly.
4. Ground Prep and Structural Base — Once permits are granted, physical construction begins. This covers land preparation, laying the structural base, and running initial plumbing and electrical conduits.
5. Framing, Roofing, and Exterior Work — Walls and roof systems go up followed by insulation, sheathing, and exterior cladding. At this stage, the ADU transforms from a concept to a building.
6. MEP Systems Rough-In — Skilled tradespeople install the heating, cooling, drainage, and power infrastructure that make the ADU operationally complete. All work is inspected at each code checkpoint throughout ADU construction.
7. Interior Completion and City Sign-Off — Trim, appliances, tile, and lighting are installed and finished to your specifications. A final city inspection issues the certificate of occupancy and the unit is officially approved for use.

Who Is a Good Candidate for ADU Construction?

People who see the greatest return from ADU construction typically fall into a few recognizable groups. If you have a residential property with available square footage under zoning rules, you're already a strong candidate. Homeowners hoping to offset mortgage costs through rental are among the most motivated ADU construction clients, along with families navigating multigenerational living situations.

Another strong candidate is someone who needs a dedicated professional workspace 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.

Homeowners who may want to pause and evaluate 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 recommend the right path forward.

ADU Construction Frequently Asked Questions

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

The complete duration for ADU construction typically ranges from six to fourteen months, influenced by the type of unit being built and how quickly approvals come through. The approval phase alone can take two to four months in San Jose, so starting early is important. Smaller detached units often finish in the lower end of the range, while custom detached builds fall toward the upper end of the timeline.

What does ADU construction typically cost?

Pricing depends on many factors based on whether it's a conversion or new construction. In the San Jose area, ADU construction generally falls between $150,000 to $400,000 or more for a standalone backyard unit. Interior conversion projects are generally priced lower, sometimes starting around $80,000 depending on scope. An accurate budget can only be given after completing a formal feasibility evaluation.

Is ADU construction disruptive while it's underway?

The level of disruption depends on the project's location on your property. New construction in the rear yard are generally the least intrusive, since work happens away from the main house. Garage conversions or attached additions may involve some shared wall work during certain phases of construction. Brother & Brother Builders keeps you informed about any phases that may affect your routine.

Do I need to vacate the property 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 stay in your primary unit throughout the build. There are edge cases if interior conversion work touches shared systems in ways that briefly affect habitability. The team at Brother & Brother Builders will flag these situations during the pre-construction consultation.

How long will an ADU built through professional ADU construction last?

A well-built ADU is designed to last as long as the main residence — indefinitely with proper upkeep. How long it lasts comes down to the systems installed, how consistently minor repairs are addressed, and how proactively issues are resolved over time. We select commercial-grade materials and build to current California residential standards to ensure lasting performance.

ADU Construction for Local Homeowners

San Jose's neighborhoods offer a diverse mix of property types that are well suited for ADU construction. Homeowners in the Willow Glen neighborhood often discover their properties are well configured for ADU builds. Neighborhoods near Blossom Hill Road are increasingly popular for ADU construction as housing demand rises. From neighborhoods near the Guadalupe River Park corridor to those near Branham Lane, our team has likely worked nearby.

The City of San Jose's building department applies particular standards for ADU construction that experienced builders know well. Proximity to transit corridors can impact the design approach for a given ADU project. Our team's knowledge of these local conditions means smoother project delivery from design through the final walkthrough.

Book Your ADU Construction Assessment Today

Should you be thinking about how to move forward with ADU construction, Brother & Brother Builders is here to help. Our builders provide proven skills in ADU construction including all types of project types — from modest studio builds to fully independent secondary homes. The process begins with a comprehensive site assessment where we learn what you're trying to accomplish and share clear expectations of what the project will involve.

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 help you take the next step. ADU construction is a significant investment — and we want to make sure it's the right one for you.

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