Brother & Brother Builders

Expand Your Home with Quality 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 creates a powerful new living space on your existing property — whether you want to house a family member. Brother & Brother Builders adu construction CA has supported hundreds of local homeowners turn these plans to life with skill and transparency.

The interest in ADU construction has surged in recent years, and it's no mystery. California state law now makes it easier for homeowners to add these secondary units, and local municipalities like San Jose have embraced the trend as a way to increase density responsibly. Whether you're building a detached backyard cottage, a garage conversion, or an attached addition, ADU construction offers greater control over how your property serves your household.

At Brother & Brother Builders, we bring years of hands-on experience to every ADU construction build. Our team knows the San Jose building codes, the engineering considerations, and the design choices that make an ADU functional. If you've been thinking about what ADU construction could do for your property, this guide explains everything you need to know.

What Is an ADU Build?

ADU construction refers to 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 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 team evaluate property boundaries, available square footage, and infrastructure capacity. From there, design plans are prepared and submitted to the relevant municipal authority. Once the paperwork is cleared, ADU construction moves into the physical build phase — which encompasses site preparation, framing, mechanical systems, weatherproofing, and interior finishing. The result is a fully functional living unit connected to or independent of your main home.

The difference between a good and a great ADU build is the level of craftsmanship at every stage. Products need to be chosen to align with the neighborhood's character. Systems like wiring and water supply must be built for long-term residential demand. Brother & Brother Builders treats each project with the same high standards we use on major custom home projects.

Key Reasons to Choose ADU Construction

• Higher Resale Potential — ADU construction contributes significant 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, creating ongoing passive income for the homeowner.
• Space for Loved Ones — ADU construction gives aging parents a self-contained residence without leaving the property.
• Design Flexibility — From two-bedroom configurations, ADU construction can be tailored to your household's priorities.
• Streamlined Approval Process — Recent state legislation has minimized the permitting obstacles associated with ADU construction, resulting in a timeline that is faster and more affordable than ever before.
• Sustainable Land Use — Building an ADU works within your current footprint instead of requiring new development, which supports broader sustainability goals.
• Independent Living Areas — Unlike a bedroom addition, ADU construction creates a truly separate unit where occupants have full privacy.
• Long-Term Investment Security — A well-built ADU remains an asset for decades, providing both usable housing and equity growth.

The ADU Construction Process Step by Step

1. Property Walkthrough and Feasibility Check — Our experts review your property to evaluate setbacks, lot coverage limits, and utility connections. This phase answers exactly what ADU types will work before any time is invested in drawings.
2. Custom Design and Architectural Planning — Our design team create precise architectural drawings based on your goals. Space is thoughtfully allocated to optimize daily use.
3. Permit Submission and Municipal Review — ADU construction in San Jose demands documentation to the city's building department for review and approval. Brother & Brother Builders coordinates the permitting on your behalf, resolving any revision requests 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 establishing utility connections.
5. Shell Construction and Exterior Finishing — Walls and roof systems go up followed by insulation, sheathing, and exterior cladding. This phase, the ADU transforms from a concept to a building.
6. Interior Systems and Infrastructure — Skilled tradespeople install the water supply, drain lines, and electrical panel that make the ADU operationally complete. Inspections are completed at required milestones throughout ADU construction.
7. Interior Completion and City Sign-Off — Flooring, cabinetry, fixtures, paint are fitted and completed to the approved plan. A last official inspection confirms the unit is code-compliant and your new space is cleared for use.

Who Is a Good Candidate for ADU Construction?

Homeowners who benefit most from ADU construction often belong to a few recognizable groups. If you are a homeowner with available square footage under zoning rules, you're already well-positioned. Homeowners looking to generate income through rental are among the most motivated ADU construction clients, along with families navigating multigenerational living situations.

ADU construction also suits someone who needs a dedicated professional workspace and wants a separate office or studio space that is distinct 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 long-term value is proven.

Homeowners who may want to pause and evaluate include properties with significant setback limitations. Very small lots or properties with easements may require additional review. Brother & Brother Builders reviews each property individually and honestly to recommend the right path forward.

ADU Construction Common Questions Answered

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

The full timeline for ADU construction commonly spans six to fourteen months, based on the project scope and local permitting timelines. Permitting alone can take several months in San Jose, so beginning the process sooner rather than later is wise. Smaller detached units may complete more quickly, while custom detached builds fall toward the upper end of the timeline.

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 typically ranges from $150,000 to $400,000 or more for a standalone backyard unit. Garage conversions tend to cost less, sometimes between $75,000 and $140,000. A detailed estimate can only be given after completing a thorough property review.

Is ADU construction disruptive while it's underway?

The day-to-day impact depends on where the ADU is being built. Detached backyard builds are generally the least intrusive, since the construction zone is separate. Interior conversions may create short-term inconveniences during specific stages like framing or MEP rough-in. We provide advance notice about what to expect at each stage.

Do I need to leave my home during ADU construction?

Generally speaking, you are not required to vacate your house during ADU construction. Most builds are structured to allow you continue living in the home throughout the process. Exceptions may arise if major utility upgrades affect the main house in ways that require short-term access disruption. Our construction supervisors will discuss these scenarios 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. Durability depends to the quality of materials used, whether the unit is properly cared for, and if mechanical components are maintained on schedule. Brother & Brother Builders specifies 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 perfectly suited for ADU construction. Property owners near the Almaden Valley area have found their lots are well configured for ADU builds. Neighborhoods near Blossom Hill Road are increasingly popular for ADU construction as multigenerational living becomes more common. If you're located closer to Evergreen, our team has project experience in the area.

The City of San Jose's building department has developed specific protocols 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 the San Jose permitting environment means smoother project delivery from the first meeting to the final inspection.

Start Your ADU Construction Assessment Today

If you're ready to explore what an ADU could look like on your lot, Brother & Brother Builders is ready to guide you. We bring proven skills in ADU construction including all types of project types — from modest studio builds to multi-room backyard residences. Every project starts with a comprehensive site assessment where we learn what you're trying to accomplish and give you a realistic picture of what ADU construction on your property will look like.

Reach out to our team to begin the conversation. Even if you're just exploring the idea, we enjoy answer questions, share examples of our work and make sure you feel confident before committing. 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