Transform Your Property with Expert ADU Construction
Property owners throughout San Jose, CA are finding that adding an accessory dwelling unit is one of the most rewarding investments they can make. ADU construction provides a powerful new living space on your existing property — whether you want to create a private workspace. Brother & Brother Builders has supported hundreds of local homeowners turn these plans 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 streamlined permitting for homeowners to construct these secondary units, and local municipalities like San Jose have supported 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 serves your household.
At Brother & Brother Builders, we draw on extensive hands-on experience to every ADU construction project. Our team knows the San Jose building codes, the engineering details, and the aesthetic decisions that make an ADU truly livable. If you've been thinking about what ADU construction could look like on your property, this guide explains everything you need to know.
What Is an ADU Build?
ADU construction refers to the process of designing, permitting, and building an accessory dwelling unit on a residential property. An accessory dwelling unit is a complete living space — equipped with a kitchen, bathroom, sleeping area, and its own entryway — 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 process begins with a detailed site assessment, 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 approvals are in place, ADU construction enters the physical build phase — which encompasses site preparation, framing, roofing, plumbing, electrical, insulation. The result is a move-in-ready living unit adjacent to or detached from your main home.
What separates excellent ADU construction from an average project is the attention to detail at every stage. Components should be specified to match the primary home's aesthetic. Systems like wiring and water supply must be built for long-term residential demand. Brother & Brother Builders treats each project with the same high standards we apply to large-scale custom home projects.
Key Benefits 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 is leasable 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 losing proximity to the family.
- Personalized Layouts — From open-plan one-bedrooms, ADU construction can be tailored to your household's priorities.
- Faster Permitting in California — Recent state legislation has reduced 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 uses your existing lot instead of consuming open land, which aligns with sustainability goals.
- Privacy for All Residents — Unlike a bedroom addition, ADU construction delivers a genuinely independent unit where residents have their own space.
- Lasting Financial Benefit — A well-built ADU holds its value for decades, providing both usable housing and equity growth.
The ADU Construction Process Step by Step
- Site Evaluation and Zoning Analysis — Our team visits your property to determine what type of ADU is allowed and where it can be placed. This step tells you exactly what can be built before any resources go toward planning.
- Architectural Drafting and Space Planning — Experienced draftspeople create precise architectural drawings tailored to your needs. Layouts are carefully considered to create practical, comfortable living.
- 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, responding to review feedback promptly.
- Excavation and Foundation Installation — Once permits are approved, the build starts. This covers land preparation, laying the structural base, and running initial plumbing and electrical conduits.
- Structural Framing and Weatherproofing — Walls and roof systems go up followed by roofing, siding, windows, and exterior doors. This phase, the ADU transforms from a concept to a building.
- Mechanical, Electrical, and Plumbing Installation — Skilled tradespeople install the water supply, drain lines, and electrical panel that make the ADU ready for occupancy. All work is inspected at designated stages throughout ADU construction.
- Interior Completion and City Sign-Off — Countertops, hardware, finishes, and fixtures are installed and finished to your specifications. A closing municipal review grants legal occupancy status and the ADU is ready for use.
Who Is a Good Candidate for ADU Construction?
Property owners who are best suited from ADU construction often belong to a few recognizable groups. If you have a residential property with a backyard, garage, or basement that could be converted, you're already in a good starting place. Homeowners looking to generate income through rental are among the most common ADU construction clients, along with families navigating multigenerational living situations.
Another strong candidate is someone who needs a dedicated professional workspace and wants a private work environment that is distinct from your family's daily life. Real estate-minded homeowners who already own residential properties are also well suited for ADU construction, since the long-term value is proven.
Those who should discuss alternatives first include sites with unusual utility access challenges. Parcels in historic districts or HOA-restricted communities may face additional constraints. Our team can assess each property case by case to recommend the right path forward.
ADU Construction FAQ
How long does ADU construction usually take from start to finish?
The total process for ADU construction commonly spans six to fourteen months, based on the project scope and how quickly approvals come through. Permitting alone can take several months in San Jose, so beginning the process sooner rather than later is wise. Simpler garage conversions can move faster, while multi-room detached cottages require more time.
What does ADU construction usually run in terms of budget?
Costs vary widely based on project complexity and finishes selected. In the San Jose area, ADU construction generally falls between $150,000 to $400,000 or more for a detached new build. Interior conversion projects tend to cost less, sometimes between $75,000 and $140,000. An accurate budget can only be produced following a full site assessment.
Is ADU construction intrusive 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. Interior conversions may create short-term inconveniences during specific stages like framing or MEP rough-in. Our team communicates clearly about upcoming work and timelines.
Do I need to move out during ADU construction?
For the majority of homeowners, you are not required to vacate your house during ADU construction. The vast majority of projects are set up to let you stay in your primary unit throughout the build. Exceptions may arise if significant structural connections require temporary shutoffs in ways that temporarily click here impact livability. Our construction supervisors 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 is designed to last as long as any standard residential structure — often several decades with routine maintenance. Durability depends to the systems installed, how well routine maintenance is performed, and if mechanical components are maintained on schedule. Our builds use residential-grade products rated for longevity and comply with all local building codes to deliver a structure that stands the test of time.
ADU Construction for Local Homeowners
The communities throughout San Jose provide a wide range of property types that are perfectly suited for ADU construction. Property owners near the Almaden Valley area have found their lots work well for both attached and detached projects. Communities around the Capitol Expressway corridor have seen growing ADU activity as families expand. If you're located closer to Evergreen, our team knows the permitting landscape well.
Local regulatory bodies in this area has developed specific protocols for ADU construction that require a builder familiar with local expectations. Proximity to transit corridors can affect how quickly permits are approved for a given ADU project. Our team's knowledge of this region's building landscape means fewer surprises from the first meeting to the final inspection.
Start Your ADU Construction Consultation Today
When you want to move forward with ADU construction, Brother & Brother Builders is here to help. We bring proven skills in ADU construction including all types of project types — from small attached additions to fully independent secondary homes. Our approach opens with a detailed, no-pressure consultation where we understand your vision and give you a realistic picture of what's achievable.
Contact Brother & Brother Builders to set up your consultation. No matter where you are in the decision-making process, we enjoy walk through your options, review completed projects and make sure you feel confident before committing. ADU construction is a significant investment — 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