Brother & Brother Builders

Transform Your Property with Expert ADU Construction

Property owners throughout San Jose, CA are discovering that adding an accessory dwelling unit is one of the smartest 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 has guided hundreds of local homeowners see these visions to life with precision and integrity.

The interest in ADU construction has increased significantly in recent years, and it's no mystery. California state law has simplified the process 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 want to build a detached backyard cottage, a garage conversion, or an attached addition, ADU construction gives you more control over how your property functions.

At Brother & Brother Builders, we draw on extensive hands-on experience to every ADU construction build. Our team is familiar with city and county requirements, the engineering requirements, and the design choices that make an ADU truly livable. Should you want to learn about what ADU construction could do 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 complete living space — including 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 interior space reconfigurations.

Mechanically, the work starts with a detailed site assessment, where our team 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 encompasses site preparation, framing, HVAC, drywall, flooring, and exterior finishes. The result is a move-in-ready living unit adjacent to or detached from your main home.

What sets quality ADU construction apart is the level of craftsmanship at every stage. Products need to be chosen to align with the neighborhood's character. Systems like HVAC and drainage 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 Advantages ADU Construction

• Higher Resale Potential — 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 can be rented as a long-term rental or short-term vacation unit, generating steady monthly revenue for the homeowner.
• Multi-Generational Living — ADU construction provides adult children a self-contained residence without moving to another neighborhood.
• Design Flexibility — From open-plan one-bedrooms, ADU construction may be customized to your specific needs.
• Streamlined Approval Process — Recent state legislation has cut down the permitting obstacles associated with ADU construction, creating a path that is faster and more affordable than ever before.
• Responsible Property Development — Building an ADU uses your existing lot 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 residents have their own space.
• Long-Term Investment Security — A well-built ADU continues to produce returns for the long haul by offering both usable housing and equity growth.

The ADU Construction Journey Step by Step

1. Initial Property Assessment and Feasibility Review — Our team visits your property to analyze zoning rules, slope conditions, and available square footage. This stage clarifies exactly what ADU types will work before any resources go toward planning.
2. Architectural Drafting and Space Planning — Our design team create detailed floor plans reflecting your priorities. Space is thoughtfully allocated to maximize function and livability.
3. Permit Submission and Municipal Review — ADU construction in San Jose demands documentation to the city's building department for sign-off and verification. We manage this entire process on your behalf, responding to review feedback promptly.
4. Excavation and Foundation Installation — Once permits are granted, the build starts. This covers land preparation, laying the structural base, and setting up utilities.
5. Framing, Roofing, and Exterior Work — Framing is completed followed by roofing, siding, windows, and exterior doors. At this stage, the ADU takes its visible shape.
6. MEP Systems Rough-In — Licensed subcontractors install the plumbing lines, electrical wiring, and HVAC systems that make the ADU operationally complete. Every system is reviewed at required milestones throughout ADU construction.
7. Interior Finishing and Final Inspections — Trim, appliances, tile, and lighting are fitted and completed to the approved plan. A closing municipal review grants legal occupancy status and your new space is cleared for use.

Who Is a Right Fit for ADU Construction?

Homeowners who benefit most from ADU construction generally fit within a few common profiles. If you own a single-family home with a backyard, garage, or basement that could be converted, you're already well-positioned. Homeowners hoping to offset mortgage costs through rental are among the most financially driven ADU construction clients, along with families supporting elderly parents.

ADU construction also suits someone who works from home and wants a private work environment that remains away from your family's daily life. Real estate-minded homeowners who already own residential properties are also prime candidates for ADU construction, since rental income frequently offsets build costs.

Homeowners who may want to pause and evaluate include properties with significant setback limitations. Parcels in historic districts or HOA-restricted communities may face additional constraints. Our team can assess each property on its own merits to provide realistic options.

ADU Construction Frequently Asked Questions

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

The full timeline for ADU construction commonly spans six to fourteen months, based on the project scope and city review schedules. City review on its own can take several months in San Jose, so starting early is important. Smaller detached units may complete more quickly, while larger new construction ADUs require more time.

What does ADU construction usually run in terms of budget?

Pricing depends on many factors based on whether it's a conversion or new construction. Locally, ADU construction commonly costs $150,000 to $400,000 or more for a detached new build. Interior conversion projects often come in under, sometimes between $75,000 and $140,000. A precise cost projection can only be developed after 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 the construction zone is separate. Garage conversions or attached additions may involve some shared wall work during key milestones. Brother & Brother Builders keeps you informed about what to expect at each stage.

Do I need to vacate the property during ADU construction?

For the majority of homeowners, you do not need to vacate your main home during ADU construction. Most builds are set up to let you stay in your primary unit throughout the process. Exceptions may arise if significant structural connections require temporary shutoffs in ways that temporarily impact livability. Our project managers read more will discuss these scenarios during the kickoff meeting.

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

A well-built ADU should last as long as your primary home — indefinitely with proper upkeep. How long it lasts comes down to the standard of construction, whether the unit is properly cared for, and how proactively issues are resolved over time. We select high-quality components and build to current California residential standards to deliver a structure that stands the test of time.

ADU Construction for San Jose Homeowners

Residential areas across San Jose present a variety 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 are increasingly popular for ADU construction as housing demand rises. If you're located closer to Evergreen, our team knows the permitting landscape well.

San Jose's permitting office applies particular standards 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 design through the final walkthrough.

Start Your ADU Construction Assessment Today

When you want to move forward with ADU construction, Brother & Brother Builders is the team to call. Our builders provide licensed expertise in ADU construction including all types of project types — from small attached additions to multi-room backyard residences. The process begins with a detailed, no-pressure consultation where we listen to your goals and provide an honest assessment of what the project will involve.

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 make sure you feel confident before committing. Building an ADU is a major decision — and we're committed to helping you get it right.

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