Transform Your Property with Quality ADU Construction
Property owners throughout San Jose, CA are discovering that adding an accessory dwelling unit is one of the most rewarding investments they can make. ADU construction opens the door to a versatile new living space on your existing property — whether you want to create a private workspace. Brother & Brother Builders has guided hundreds of local homeowners turn these plans to life with craftsmanship and integrity.
The interest in ADU construction has grown rapidly in recent years, and it's no mystery. California state law now makes it easier for homeowners to build these secondary units, and local municipalities like San Jose have supported the trend as a way to expand the housing supply. Whether you want to build a detached backyard cottage, a garage conversion, or an attached addition, ADU construction offers greater control over how your property works.
At Brother & Brother Builders, we draw on extensive hands-on experience to every ADU construction build. Our team understands the local permitting process, the engineering considerations, and the planning steps that make an ADU functional. Should you want to learn about what ADU construction could do for your property, this guide covers everything you need to know.
What Is an ADU Build?
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 fully independent living space — featuring a kitchen, bathroom, sleeping area, and its own entrance — 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 interior space reconfigurations.
Mechanically, everything kicks off with a detailed site assessment, where our team evaluate setbacks, zoning, utility access, and structural feasibility. From there, blueprints are prepared and submitted to the relevant municipal authority. Once approvals are in place, ADU construction moves into the physical build phase — which includes foundation work, framing, HVAC, drywall, flooring, and exterior finishes. The result is a move-in-ready living unit attached to or separate from your main home.
What sets quality ADU construction apart is the attention to detail at every stage. Materials must be selected to complement the existing structure. Systems like plumbing and electrical must be sized for independent daily use. Brother & Brother Builders approaches every build with the same technical discipline we bring to full custom home projects.
Key Advantages ADU Construction
- Boosted Home Equity — ADU construction contributes significant 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, providing a consistent income stream for the homeowner.
- Space for Loved Ones — ADU construction gives aging parents a comfortable home of their own without moving to another neighborhood.
- Customization Options — From two-bedroom configurations, ADU construction can be tailored to your specific needs.
- Simplified Regulatory Path — Recent state legislation has minimized the permitting obstacles associated with ADU construction, making the process 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 supports broader sustainability goals.
- Independent Living Areas — Unlike a bedroom addition, ADU construction delivers a genuinely independent unit where occupants have full privacy.
- Lasting Financial Benefit — A well-built ADU remains an asset for many years and generates both functional space and financial upside.
The ADU Construction Journey Step by Step
- Property Walkthrough and Feasibility Check — Our builders assess your property to evaluate setbacks, lot coverage limits, and utility connections. This phase answers exactly what's possible before any resources go toward planning.
- Architectural Drafting and Space Planning — Our design team create comprehensive blueprints reflecting your priorities. Space is thoughtfully allocated to optimize daily use.
- Permitting and City Approval — ADU construction in San Jose requires submitting plans to the city's building department for sign-off and verification. Brother & Brother Builders coordinates the permitting on your behalf, resolving any revision requests promptly.
- Excavation and Foundation Installation — Once permits are granted, on-site work kicks off. This covers land preparation, completing foundation work, and running initial plumbing and electrical conduits.
- Structural Framing and Weatherproofing — The structural frame is erected followed by roofing, siding, windows, and exterior doors. During this step, the ADU becomes recognizable as a structure.
- Interior Systems and Infrastructure — Skilled tradespeople install the plumbing lines, electrical wiring, and HVAC systems that make the ADU fully functional. Inspections are completed at required milestones throughout ADU construction.
- Interior Completion and City Sign-Off — Flooring, cabinetry, fixtures, paint are installed and finished to the approved plan. A final city inspection 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 typically fall into a few common profiles. If you own a single-family home with available square footage under zoning rules, you're already well-positioned. Homeowners looking to generate income through rental are among the most financially driven ADU construction clients, along with families accommodating adult children who need housing.
You may also be someone who runs a small business and wants a detached creative or business space that is distinct from your family's daily life. Property investors and rental owners who want to maximize their land are also prime candidates for ADU construction, since the long-term value is proven.
Those who should discuss alternatives first include lots that are below minimum size thresholds. Very small lots or properties with easements may face additional constraints. Our team can assess each property individually and honestly to recommend the right path forward.
ADU Construction Common Questions Answered
How long does ADU construction typically take from start to finish?
The full timeline for ADU construction commonly spans six to fourteen months, influenced by the type of unit being built and local permitting timelines. Permitting alone can take several months in San Jose, so starting early is important. Smaller detached units often finish in the lower end of the range, while larger new construction ADUs fall toward the upper end of the timeline.
What does ADU construction typically cost?
Costs vary widely based on the type and size of here the ADU. In the San Jose area, ADU construction generally falls between $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 given after completing a thorough property review.
Is ADU construction difficult to live through while it's underway?
How much the build affects daily life depends on where the ADU is being built. Detached backyard builds are generally the least intrusive, since the construction zone is separate. Projects that connect to the main structure may involve some shared wall work during certain phases of construction. Our team communicates clearly about what to expect at each stage.
Do I need to leave my home during ADU construction?
Generally speaking, you won't have to vacate your main home during ADU construction. Most builds are set up to let you remain on the property throughout the construction timeline. There are edge cases if interior conversion work touches shared systems in ways that briefly affect habitability. Our construction supervisors will walk you through any potential disruptions during the planning phase.
How long will an ADU built through professional ADU construction last?
Any ADU built to code with professional oversight should 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. Brother & Brother Builders specifies high-quality components and comply with all local building codes to protect your investment for the long haul.
ADU Construction for San Jose Homeowners
Residential areas across San Jose present a wide range of property types that are well suited for ADU construction. Homeowners in the Willow Glen neighborhood frequently see their parcels are well configured for ADU builds. Neighborhoods near Blossom Hill Road are increasingly popular for ADU construction as multigenerational living becomes more common. Whether your property is near downtown San Jose, our team has project experience in the area.
Local regulatory bodies in this area applies particular standards for ADU construction that require a builder familiar with local expectations. Location near major arterials like Story Road or Tully Road can influence utility connection requirements for a given ADU project. Our team's knowledge of this region's building landscape means more accurate timelines and budgets from the first meeting to the final inspection.
Start Your ADU Construction Assessment Today
Should you be thinking about how to explore what an ADU could look like on your lot, Brother & Brother Builders is here to help. Our experts offer years of hands-on experience in ADU construction for many different project types — from simple garage conversions to large custom detached cottages. Every project starts with a thorough and honest property review where we learn what you're trying to accomplish and share clear expectations of what ADU construction on your property will look like.
Reach out to our team to set up your consultation. Whether you're in the early stages of planning, we enjoy walk through your options, review completed projects and help you take the next step. 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