Transform Your Property with Quality ADU Construction
Families in San Jose, CA are finding that adding an accessory dwelling unit is one of the smartest investments they can make. ADU construction opens the door to a flexible new living space on your existing property — whether you want to house a family member. Brother & Brother Builders has supported hundreds of local homeowners bring these projects to life with precision and care.
The interest in ADU construction has increased significantly in recent years, and it's easy to understand read more 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 a way to expand the housing supply. Whether you're building a detached backyard cottage, a garage conversion, or an attached addition, ADU construction gives you more control over how your property serves your household.
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 details, and the aesthetic decisions that make an ADU truly livable. Should you want to learn about what ADU construction could look like on your property, this guide covers everything you need to know.
What Is ADU Construction?
ADU construction describes the process of planning, approving, and constructing an accessory dwelling unit on a residential property. An accessory dwelling unit is a fully independent living space — equipped with a kitchen, bathroom, sleeping area, and its own access point — that exists on the same lot as a primary residence. ADU construction includes various structural types, including detached backyard units, attached additions, garage conversions, and even below-grade dwelling units.
Mechanically, the work starts with a detailed site assessment, where our team evaluate property boundaries, available square footage, and infrastructure capacity. From there, architectural drawings are prepared and submitted to the relevant municipal authority. Once the paperwork is cleared, ADU construction transitions to the physical build phase — which includes foundation work, framing, mechanical systems, weatherproofing, and interior finishing. The result is a completely finished living unit attached to or separate from your main home.
What sets quality ADU construction apart is the attention to detail at every stage. Products need to be chosen to complement the existing structure. Systems like plumbing and electrical must be designed to handle full-time occupancy. Brother & Brother Builders handles every ADU construction job with the same technical discipline we apply to large-scale 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.
- Rental Income Potential — A completed ADU may be listed as a long-term rental or short-term vacation unit, generating steady monthly revenue for the homeowner.
- Multi-Generational Living — ADU construction offers family members a self-contained residence without moving to another neighborhood.
- Customization Options — From open-plan one-bedrooms, ADU construction may be customized to your household's priorities.
- Simplified Regulatory Path — Recent state legislation has minimized the red tape associated with ADU construction, resulting in a timeline that is faster and more affordable than ever before.
- Efficient Use of Your Lot — Building an ADU uses your existing lot instead of consuming open land, which supports broader sustainability goals.
- Separate Entrances and Spaces — Unlike a bedroom addition, ADU construction delivers a genuinely independent unit where tenants live autonomously.
- Long-Term Investment Security — A well-built ADU holds its value for the long haul by offering both usable housing and equity growth.
The ADU Construction Journey Step by Step
- Site Evaluation and Zoning Analysis — Our experts review your property to evaluate setbacks, lot coverage limits, and utility connections. This stage clarifies exactly what can be built before any money is spent on design.
- Blueprint Development and Layout Design — Experienced draftspeople create precise architectural drawings tailored to your needs. Space is thoughtfully allocated to optimize daily use.
- Filing for Building Permits — ADU construction in San Jose demands documentation to the city's building department for inspection and clearance. Brother & Brother Builders coordinates the permitting on your behalf, responding to review feedback promptly.
- Excavation and Foundation Installation — Once permits are granted, the build starts. This includes grading the site, pouring the concrete foundation, and establishing utility connections.
- Framing, Roofing, and Exterior Work — The structural frame is erected followed by insulation, sheathing, and exterior cladding. At this stage, the ADU takes its visible shape.
- Interior Systems and Infrastructure — Certified technicians install the water supply, drain lines, and electrical panel that make the ADU fully functional. All work is inspected at required milestones throughout ADU construction.
- Interior Completion and City Sign-Off — Flooring, cabinetry, fixtures, paint are placed and inspected to the approved plan. A closing municipal review issues the certificate of occupancy and your new space is cleared for use.
Who Is a Strong Candidate for ADU Construction?
Homeowners who benefit most from ADU construction generally fit within a few clear categories. If you are a homeowner with a backyard, garage, or basement that could be converted, you're already in a good starting place. Homeowners hoping to offset mortgage costs through rental are among the most motivated ADU construction clients, along with families navigating multigenerational living situations.
You may also be someone who 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 already own residential properties are also a natural fit for ADU construction, since the return on investment is well-documented.
Those who should discuss alternatives first include sites with unusual utility access challenges. Parcels in historic districts or HOA-restricted communities may need a modified approach. 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 generally take from start to finish?
The total process for ADU construction typically ranges from six to fourteen months, depending on design complexity and local permitting timelines. Permitting alone can take several months in San Jose, so beginning the process sooner rather than later is wise. Simpler garage conversions may complete more quickly, while larger new construction ADUs require more time.
What does ADU construction typically cost?
Pricing depends on many factors based on project complexity and finishes selected. In the San Jose area, ADU construction commonly costs $150,000 to $400,000 or more for a fully custom construction. Garage conversions tend to cost less, 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 day-to-day impact depends on where the ADU is being built. Detached backyard builds are usually easier to live alongside, since work happens away from the main house. Garage conversions or attached additions may require temporary access during certain phases of construction. Our team communicates clearly about any phases that may affect your routine.
Do I need to move out during ADU construction?
Generally speaking, you do not need to vacate your main home during ADU construction. Most job sites are designed so that you remain on the property throughout the construction timeline. Exceptions may arise if significant structural connections require temporary shutoffs in ways that temporarily impact livability. The team at Brother & Brother Builders will discuss these scenarios during the pre-construction consultation.
How long will an ADU built through professional ADU construction hold up?
A well-built ADU can be expected to last as long as any standard residential structure — typically 50 years or more. Longevity is tied to the systems installed, how well routine maintenance is performed, and how proactively issues are resolved over time. Our builds use high-quality components and build to current California residential standards to protect your investment for the long haul.
ADU Construction for San Jose Homeowners
The communities throughout San Jose provide a diverse mix of property types that are perfectly suited for ADU construction. Property owners near the Almaden Valley area often discover their properties work well for both attached and detached projects. Communities around the Capitol Expressway corridor have seen growing ADU activity as families expand. Whether your property is near downtown San Jose, our team has project experience in the area.
San Jose's permitting office follows defined procedures 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 familiarity with the San Jose permitting environment means fewer surprises from design through the final walkthrough.
Schedule Your ADU Construction Planning Session 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 licensed expertise in ADU construction including all types of project types — from simple garage conversions to multi-room backyard residences. The process begins with a thorough and honest property review where we listen to your goals and share clear expectations of what's achievable.
Contact Brother & Brother Builders to set up your consultation. No matter where you are in the decision-making process, our team is happy to discuss timelines, costs, and design possibilities 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