Unlock New Space with Professional ADU Construction
Homeowners across San Jose, CA are realizing 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 generate rental income. Brother & Brother Builders has guided hundreds of local homeowners turn these plans to life with precision and transparency.
The popularity of ADU construction has grown rapidly in recent years, and it's easy to understand why. California state law has simplified the process for homeowners to construct these secondary units, and local municipalities like San Jose have supported the trend as website a way to address housing needs. 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 works.
At Brother & Brother Builders, we bring years of hands-on experience to every ADU construction project. Our team knows the San Jose building codes, the engineering details, and the design choices that make an ADU beautiful. Should you want to learn about what ADU construction could mean for your property, this guide explains everything you need to know.
What Is the ADU Construction Process?
ADU construction describes the process of planning, approving, and constructing 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 basement or interior conversions.
Mechanically, the work starts with a detailed site assessment, where our builders evaluate setbacks, zoning, utility access, and structural feasibility. From there, architectural drawings are prepared and submitted to the city for permit approval. 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 fully functional living unit adjacent to or detached from your main home.
What sets quality ADU construction apart is the depth of planning at every stage. Components should be specified to align with the neighborhood's character. Systems like plumbing and electrical must be sized for independent daily use. Brother & Brother Builders approaches every build with the same high standards we use on major custom home projects.
Key Reasons to Choose ADU Construction
- Increased Property Value — 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 may be listed as a long-term rental or short-term vacation unit, generating steady monthly revenue for the homeowner.
- Housing for Extended Family — ADU construction offers family members a comfortable home of their own without moving to another neighborhood.
- Design Flexibility — From modern studio layouts, ADU construction is adaptable to your specific needs.
- Faster Permitting in California — Recent state legislation has reduced the red tape associated with ADU construction, resulting in a timeline that is faster and more cost-efficient 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 delivers a genuinely independent unit where residents have their own space.
- Long-Term Investment Security — A well-built ADU continues to produce returns for many years and generates both usable housing and equity growth.
The ADU Construction Journey Step by Step
- Initial Property Assessment and Feasibility Review — 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.
- Architectural Drafting and Space Planning — Licensed architects and designers create detailed floor plans based on your goals. Layouts are carefully considered to create practical, comfortable living.
- Permit Submission and Municipal Review — ADU construction in San Jose requires submitting plans to the city's building department for review and approval. We manage this entire process on your behalf, addressing any city comments promptly.
- Site Preparation and Foundation Work — Once permits are approved, the build starts. This covers land preparation, pouring the concrete foundation, and establishing utility connections.
- Shell Construction and Exterior Finishing — Walls and roof systems go up followed by insulation, sheathing, and exterior cladding. At this stage, the ADU takes its visible shape.
- Interior Systems and Infrastructure — Licensed subcontractors install the plumbing lines, electrical wiring, and HVAC systems that make the ADU operationally complete. Inspections are completed at each code checkpoint throughout ADU construction.
- Finishes, Fixtures, and Final Walkthrough — Flooring, cabinetry, fixtures, paint are installed and finished to the agreed design. A last official inspection grants legal occupancy status and your new space is cleared for use.
Who Is a Good Candidate for ADU Construction?
Homeowners who benefit most from ADU construction generally fit within a few clear categories. If you have a residential property with enough lot space to meet setback requirements, 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 supporting elderly parents.
Another strong candidate is someone who works from home and wants a detached creative or business space that remains away from your family's daily life. Landlords and real estate investors who already own residential properties are also a natural fit 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 require additional review. Brother & Brother Builders reviews each property individually and honestly to recommend the right path forward.
ADU Construction FAQ
How long does ADU construction typically take from start to finish?
The total process for ADU construction usually runs between six to fourteen months, influenced by the type of unit being built and city review schedules. The approval phase alone can take two to four months in San Jose, so planning ahead matters. Straightforward interior conversions can move faster, while custom detached builds take longer to complete.
What does ADU construction typically cost?
Costs vary widely based on the type and size of the ADU. In the San Jose area, ADU construction typically ranges from $150,000 to $400,000 or more for a fully custom construction. Garage conversions often come in under, sometimes starting around $80,000 depending on scope. A precise cost projection can only be developed after a formal feasibility evaluation.
Is ADU construction difficult to live through while it's underway?
The level of disruption depends on the project's location on your property. Detached backyard builds are generally the least intrusive, since the crew operates at a distance from your living areas. Garage conversions or attached additions may create short-term inconveniences during key milestones. Our team communicates clearly about any phases that may affect your routine.
Do I need to leave my home during ADU construction?
Generally speaking, you do not need to vacate your house during ADU construction. Most builds are structured to allow you remain on the property throughout the process. Certain situations could require a brief departure if significant structural connections require temporary shutoffs in ways that require short-term access disruption. The team at Brother & Brother Builders will walk you through any potential disruptions during the pre-construction consultation.
How long will an ADU built through professional ADU construction hold up?
Any ADU built to code with professional oversight should last as long as your primary home — indefinitely with proper upkeep. How long it lasts comes down to the systems installed, how consistently minor repairs are addressed, and if mechanical components are maintained on schedule. Our builds use high-quality components and build to current California residential standards to protect your investment for the long haul.
ADU Construction for Local Homeowners
The communities throughout San Jose provide 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 seeing more homeowners add secondary units as housing demand rises. From neighborhoods near the Guadalupe River Park corridor to those near Branham Lane, our team has likely worked nearby.
Local regulatory bodies in this area follows defined procedures for ADU construction that experienced builders know well. Location near major arterials like Story Road or Tully Road can affect how quickly permits are approved for a given ADU project. Our team's knowledge of the San Jose permitting environment means fewer surprises from design through the final walkthrough.
Book Your ADU Construction Consultation Today
Should you be thinking about how to move forward with ADU construction, Brother & Brother Builders is ready to guide you. Our experts offer years of hands-on experience in ADU construction for many different project types — from simple garage conversions to multi-room backyard residences. Every project starts with a thorough and honest property review where we understand your vision and provide an honest assessment of what ADU construction on your property will look like.
Reach out to our team to begin the conversation. No matter where you are in the decision-making process, we're glad 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 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