Transform Your Property with Quality ADU Construction
Families in San Jose, CA are discovering 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 create a private workspace. Brother & Brother Builders has guided hundreds of local homeowners bring these projects to life with precision and transparency.
The interest in ADU construction has increased significantly in recent years, and it's easy to understand why. California state law has streamlined permitting for homeowners to construct these secondary units, and local municipalities like San Jose have embraced 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 build. Our team understands the local permitting process, the engineering requirements, and the aesthetic decisions that make an ADU functional. When you're ready to explore what ADU construction could look like on your property, this guide explains everything you need to know.
What Is the ADU Construction Process?
ADU construction refers to 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 — including a kitchen, bathroom, sleeping area, and its own access point — that sits on the same property as a primary residence. ADU construction includes various structural types, including detached backyard units, attached additions, garage conversions, and even basement or interior conversions.
Mechanically, the work starts with a comprehensive review of your lot, where our professionals evaluate property boundaries, available square footage, and infrastructure capacity. From there, blueprints are prepared and submitted to the local building department. Once the paperwork is cleared, 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. Products need to be chosen to match the primary home's aesthetic. Systems like HVAC and drainage must be built for long-term residential demand. Brother & Brother Builders handles every ADU construction job with the same technical discipline 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 generating strong equity gains 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.
- Multi-Generational Living — ADU construction gives aging parents a private, independent living space without moving to another neighborhood.
- Design Flexibility — From open-plan one-bedrooms, ADU construction is adaptable to your specific needs.
- Simplified Regulatory Path — Recent state legislation has cut down the barriers and delays associated with ADU construction, creating a path that is faster and less expensive than ever before.
- Sustainable Land Use — Building an ADU maximizes the land you already own instead of requiring new development, which contributes to sustainability goals.
- Separate Entrances and Spaces — Unlike a bedroom addition, ADU construction produces a fully self-contained unit where tenants live autonomously.
- Lasting Financial Benefit — A well-built ADU continues to produce returns for the long haul by offering both functional space and financial upside.
The ADU Construction Journey Step by Step
- Initial Property Assessment and Feasibility Review — Our builders assess your property to evaluate setbacks, lot coverage limits, and utility connections. This phase answers exactly what ADU types will work before any money is spent on design.
- Architectural Drafting and Space Planning — Licensed architects and designers create detailed floor plans tailored to your needs. Space is thoughtfully allocated to optimize daily use.
- Permit Submission and Municipal Review — ADU construction in San Jose involves filing drawings to the city's building department for inspection and clearance. Our team handles all submissions on your behalf, addressing any city comments promptly.
- Excavation and Foundation Installation — Once permits are issued, on-site work kicks off. This includes grading the site, completing foundation work, and running initial plumbing and electrical conduits.
- Shell Construction and Exterior Finishing — The structural frame is erected followed by weatherproofing and exterior finish materials. At this stage, the ADU takes its visible shape.
- Interior Systems and Infrastructure — Skilled tradespeople install the water supply, drain lines, and electrical panel that make the ADU operationally complete. Every system is reviewed at required milestones throughout ADU construction.
- Interior Finishing and Final Inspections — Flooring, cabinetry, fixtures, paint are fitted and completed to the agreed design. A last official inspection confirms the unit is code-compliant and the unit is officially approved for use.
Who Is a Right Fit for ADU Construction?
Property owners who are best suited from ADU construction typically fall into a few recognizable groups. If you have a residential property with a backyard, garage, or basement that could be converted, you're already a strong candidate. Homeowners hoping to offset mortgage costs through rental are among the most common ADU construction clients, along with families supporting elderly parents.
ADU construction also suits someone who read more runs a small business and wants a separate office or studio space that is distinct from your family's daily life. Real estate-minded homeowners who are building a portfolio are also a natural fit for ADU construction, since the long-term value is proven.
Situations where ADU construction may not be the best first step include properties with significant setback limitations. Sites with underground infrastructure conflicts may require additional review. Our experts will evaluate each property on its own merits to recommend the right path forward.
ADU Construction Common Questions Answered
How long does ADU construction typically take from start to finish?
The total process for ADU construction commonly spans six to fourteen months, depending on design complexity and how quickly approvals come through. City review on its own can take a significant portion of the overall timeline in San Jose, so starting early is important. Simpler garage conversions can move faster, while larger new construction ADUs fall toward the upper end of the timeline.
What does ADU construction typically cost?
Pricing depends on many factors based on project complexity and finishes selected. Locally, ADU construction typically ranges from $150,000 to $400,000 or more for a standalone backyard unit. Attached ADU additions are generally priced lower, sometimes starting around $80,000 depending on scope. A precise cost projection can only be given after completing a full site assessment.
Is ADU construction intrusive 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 create short-term inconveniences during certain phases of construction. Our team communicates clearly about what to expect at each stage.
Do I need to vacate the property during ADU construction?
Generally speaking, you do not need to vacate your primary residence 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 briefly affect habitability. Our project managers will walk you through any potential disruptions during the pre-construction consultation.
How long will an ADU built through professional ADU construction remain in good condition?
Any ADU built to code with professional oversight can be expected to last as long as the main residence — indefinitely with proper upkeep. Longevity is tied to the systems installed, how well routine maintenance is performed, and if mechanical components are maintained on schedule. Our builds use high-quality components and follow all code requirements to ensure lasting performance.
ADU Construction for Local 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 accommodate detached backyard units nicely. The Berryessa area have seen growing ADU activity as multigenerational living becomes more common. Whether your property is near downtown San Jose, our team has likely worked nearby.
The City of San Jose's building department applies particular standards for ADU construction that our team navigates routinely. 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 smoother project delivery from design through the final walkthrough.
Book Your ADU Construction Assessment Today
Should you be thinking about how to add an ADU to your property, Brother & Brother Builders is the team to call. Our experts offer proven skills in ADU construction for many different project types — from small attached additions to fully independent secondary homes. Our approach opens with a detailed, no-pressure consultation where we learn what you're trying to accomplish and provide an honest assessment of what the project will involve.
Get in touch with our office to schedule a site visit. Whether you're in the early stages of planning, we enjoy answer questions, share examples of our work and give you the clarity you need to move forward. ADU construction is a significant investment — and we're committed to helping you get it right.
Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632