Transform Your Property with Quality ADU Construction
Homeowners across San Jose, CA are realizing that adding an accessory dwelling unit is one of the most rewarding investments they can make. ADU construction creates a powerful 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 care.
The popularity of ADU construction has surged in recent years, and it's easy to understand why. California state law has streamlined permitting for homeowners to add these secondary units, and local municipalities like San Jose have encouraged 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 bring years of hands-on experience to every ADU construction project. Our team understands the local permitting process, the engineering considerations, and the planning steps that make an ADU functional. When you're ready to explore what ADU construction could look like on your property, this guide will walk you through everything you need to know.
What Is an ADU Build?
ADU construction describes the process of designing, permitting, and building an accessory dwelling unit on a residential property. An accessory dwelling unit is a self-contained living space — equipped with 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, everything kicks off with a thorough property evaluation, where our team evaluate property boundaries, available square footage, and infrastructure capacity. From there, architectural drawings are prepared and submitted to the city for click here permit approval. Once the paperwork is cleared, ADU construction moves into the physical build phase — which encompasses site preparation, framing, HVAC, drywall, flooring, and exterior finishes. The result is a fully functional living unit connected to or independent of your main home.
What separates excellent ADU construction from an average project is the level of craftsmanship at every stage. Materials must be selected to align with the neighborhood's character. Systems like plumbing and electrical must be sized for independent daily use. Brother & Brother Builders treats each project with the same professional rigor we bring to full custom home projects.
Key Benefits ADU Construction
- Boosted Home Equity — ADU construction contributes significant market value to your property, often returning more than the build cost when it's time to sell.
- Rental Income Potential — A completed ADU is leasable as a long-term rental or short-term vacation unit, providing a consistent income stream for the homeowner.
- Space for Loved Ones — ADU construction provides adult children a self-contained residence without losing proximity to the family.
- Personalized Layouts — From open-plan one-bedrooms, ADU construction is adaptable to your household's priorities.
- Streamlined Approval Process — Recent state legislation has reduced the permitting obstacles associated with ADU construction, resulting in a timeline that is faster and less expensive than ever before.
- Sustainable Land Use — Building an ADU uses your existing lot instead of expanding urban sprawl, which supports broader sustainability goals.
- Independent Living Areas — Unlike a bedroom addition, ADU construction delivers a genuinely independent unit where tenants live autonomously.
- Lasting Financial Benefit — A well-built ADU holds its value for many years and generates both livable square footage and monetary benefit.
The ADU Construction Process Step by Step
- Property Walkthrough and Feasibility Check — Our team visits your property to evaluate setbacks, lot coverage limits, and utility connections. This stage clarifies exactly what's possible before any time is invested in drawings.
- Architectural Drafting and Space Planning — Licensed architects and designers create precise architectural drawings based on your goals. Layouts are carefully considered to optimize daily use.
- Permit Submission and Municipal Review — ADU construction in San Jose requires submitting plans to the city's building department for inspection and clearance. Our team handles all submissions on your behalf, responding to review feedback promptly.
- Excavation and Foundation Installation — Once permits are issued, the build starts. This involves leveling and prepping the ground, laying the structural base, 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 transforms from a concept to a building.
- Mechanical, Electrical, and Plumbing Installation — Licensed subcontractors install the water supply, drain lines, and electrical panel that make the ADU fully functional. Inspections are completed at required milestones throughout ADU construction.
- Finishes, Fixtures, and Final Walkthrough — Trim, appliances, tile, and lighting are placed and inspected to your specifications. A last official inspection issues the certificate of occupancy and your new space is cleared for use.
Who Is a Right Fit for ADU Construction?
Property owners who are best suited from ADU construction typically fall into a few clear categories. 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 motivated ADU construction clients, along with families accommodating adult children who need housing.
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. Landlords and real estate investors who are building a portfolio are also a natural fit for ADU construction, since rental income frequently offsets build costs.
Those who should discuss alternatives first include properties with significant setback limitations. Sites with underground infrastructure conflicts may require additional review. Our team can assess each property individually and honestly to advise you on what's feasible.
ADU Construction Frequently Asked Questions
How long does ADU construction generally take from start to finish?
The complete duration for ADU construction commonly spans six to fourteen months, depending on design complexity 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. Smaller detached units can move faster, while larger new construction ADUs require more time.
What does ADU construction usually run in terms of budget?
Costs vary widely based on project complexity and finishes selected. For most projects in this region, ADU construction typically ranges from $150,000 to $400,000 or more for a detached new build. Interior conversion projects are generally priced lower, sometimes starting around $80,000 depending on scope. An accurate budget can only be given after completing a formal feasibility evaluation.
Is ADU construction intrusive while it's underway?
The level of disruption depends on the project's location on your property. Detached backyard builds are usually easier to live alongside, since work happens away from the main house. Interior conversions may require temporary access during key milestones. Our team communicates clearly about upcoming work and timelines.
Do I need to vacate the property during ADU construction?
Generally speaking, you won't have to vacate your main home during ADU construction. Most builds are designed so that you remain on the property throughout the build. There are edge cases if significant structural connections require temporary shutoffs in ways that require short-term access disruption. Our project managers will flag these situations during the planning phase.
How long will an ADU built through professional ADU construction hold up?
Any ADU built to code with professional oversight can be expected to last as long as any standard residential structure — typically 50 years or more. How long it lasts comes down to the quality of materials used, how well routine maintenance is performed, and how proactively issues are resolved over time. Our builds use residential-grade products rated for longevity and comply with all local building codes to ensure lasting performance.
ADU Construction for San Jose Homeowners
San Jose's neighborhoods offer a variety of property types that are perfectly suited for ADU construction. Property owners near the Almaden Valley area have found their lots accommodate detached backyard units nicely. Neighborhoods near Blossom Hill Road are increasingly popular for ADU construction as multigenerational living becomes more common. If you're located closer to Evergreen, our team has project experience in the area.
Local regulatory bodies in this area applies particular standards for ADU construction that our team navigates routinely. Access to infrastructure along thoroughfares like Monterey Road can influence utility connection requirements for a given ADU project. Brother & Brother Builders' experience across these local conditions means smoother project delivery from kickoff through certificate of occupancy.
Schedule Your ADU Construction Consultation Today
When you want to move forward with ADU construction, Brother & Brother Builders is here to help. We bring licensed expertise in ADU construction for many different project types — from simple garage conversions to large custom detached cottages. The process begins with a thorough and honest property review where we learn what you're trying to accomplish and give you a realistic picture of what's achievable.
Get in touch with our office to set up your consultation. Whether you're in the early stages of planning, we enjoy walk through your options, review completed projects and make sure you feel confident before committing. ADU construction is a significant investment — and our goal is to ensure it delivers real value.
Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632