Transform Your Property with Quality ADU Construction
Property owners throughout San Jose, CA are realizing that adding an accessory dwelling unit is one of the smartest investments they can make. ADU construction opens the door to 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 bring these projects to life with precision and integrity.
The demand for ADU construction has surged in recent years, and it's not hard to see why. California state law now makes it easier for homeowners to add 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 offers greater control over how your property functions.
At Brother & Brother Builders, we apply deep hands-on experience to every ADU construction build. Our team is familiar with city and county requirements, the engineering details, and the planning steps that make an ADU functional. When you're ready to explore what ADU construction could mean for your property, this guide will walk more info you through everything you need to know.
What Is the ADU Construction Process?
ADU construction involves the process of planning, approving, and constructing 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 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 below-grade dwelling units.
Mechanically, the work starts with a comprehensive review of your lot, where our team evaluate property boundaries, available square footage, and infrastructure capacity. From there, design plans are prepared and submitted to the local building department. Once approvals are in place, ADU construction enters the physical build phase — which includes foundation work, framing, roofing, plumbing, electrical, insulation. The result is a fully functional 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 match the primary home's aesthetic. Systems like wiring and water supply must be designed to handle full-time occupancy. Brother & Brother Builders approaches every build with the same professional rigor we apply to large-scale custom home projects.
Key Reasons to Choose ADU Construction
- Higher Resale Potential — 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, providing a consistent income stream for the homeowner.
- Housing for Extended Family — ADU construction provides adult children a self-contained residence without leaving the property.
- Personalized Layouts — From two-bedroom configurations, ADU construction can be tailored to your specific needs.
- Streamlined Approval Process — Recent state legislation has minimized the permitting obstacles 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 consuming open land, which contributes to sustainability goals.
- Privacy for All Residents — Unlike a bedroom addition, ADU construction delivers a genuinely independent unit where tenants live autonomously.
- Long-Term Investment Security — A well-built ADU continues to produce returns for many years and generates both functional space and financial upside.
The ADU Construction Journey Step by Step
- Initial Property Assessment and Feasibility Review — Our team visits your property to analyze zoning rules, slope conditions, and available square footage. This step tells you exactly what ADU types will work before any time is invested in drawings.
- Custom Design and Architectural Planning — Licensed architects and designers create comprehensive blueprints reflecting your priorities. Space is thoughtfully allocated to create practical, comfortable living.
- Filing for Building Permits — ADU construction in San Jose involves filing drawings to the city's building department for review and approval. We manage this entire process on your behalf, addressing any city comments promptly.
- Excavation and Foundation Installation — Once permits are approved, on-site work kicks off. This includes grading the site, completing foundation work, and establishing utility connections.
- Structural Framing and Weatherproofing — The structural frame is erected followed by roofing, siding, windows, and exterior doors. This phase, the ADU becomes recognizable as a structure.
- Mechanical, Electrical, and Plumbing Installation — Certified technicians install the plumbing lines, electrical wiring, and HVAC systems that make the ADU fully functional. Every system is reviewed at required milestones throughout ADU construction.
- Interior Finishing and Final Inspections — Trim, appliances, tile, and lighting are installed and finished to the approved plan. A last official inspection confirms the unit is code-compliant and your new space is cleared for use.
Who Is a Strong Candidate for ADU Construction?
Property owners who are best suited from ADU construction typically fall into a few recognizable groups. If you own a single-family home with enough lot space to meet setback requirements, you're already well-positioned. Homeowners wanting to add a revenue stream through rental are among the most motivated ADU construction clients, along with families navigating multigenerational living situations.
ADU construction also suits someone who needs a dedicated professional workspace and wants a detached creative or business space that is distinct from your family's daily life. Landlords and real estate investors who want to maximize their land are also prime candidates for ADU construction, since the long-term value is proven.
Homeowners who may want to pause and evaluate include lots that are below minimum size thresholds. Sites with underground infrastructure conflicts may need a modified approach. Brother & Brother Builders reviews each property case by case to advise you on what's feasible.
ADU Construction Frequently Asked Questions
How long does ADU construction typically take from start to finish?
The full timeline for ADU construction usually runs between six to fourteen months, influenced by the type of unit being built and city review schedules. Permitting alone can take several months in San Jose, so planning ahead matters. Straightforward interior conversions may complete more quickly, while larger new construction ADUs require more time.
What does ADU construction typically cost?
Costs vary widely based on whether it's a conversion or new construction. In the San Jose area, ADU construction generally falls between $150,000 to $400,000 or more for a detached new build. Garage conversions are generally priced lower, sometimes starting around $80,000 depending on scope. A precise cost projection can only be developed after a full site assessment.
Is ADU construction intrusive while it's underway?
How much the build affects daily life depends on the project's location on your property. New construction in the rear yard are usually easier to live alongside, since work happens away from the main house. Interior conversions may require temporary access during specific stages like framing or MEP rough-in. Brother & Brother Builders keeps you informed about any phases that may affect your routine.
Do I need to move out during ADU construction?
For the majority of homeowners, you are not required to vacate your main home during ADU construction. Most job sites are designed so that you stay in your primary unit throughout the build. Certain situations could require a brief departure if interior conversion work touches shared systems in ways that briefly affect habitability. Our construction supervisors will flag these situations during the planning phase.
How long will an ADU built through professional ADU construction hold up?
An ADU constructed with quality materials should last as long as your primary home — often several decades with routine maintenance. How long it lasts comes down to the systems installed, whether the unit is properly cared for, and if mechanical components are maintained on schedule. We select residential-grade products rated for longevity and build to current California residential standards to ensure lasting performance.
ADU Construction for San Jose Homeowners
San Jose's neighborhoods offer a wide range of property types that are perfectly suited for ADU construction. Residents in the Rose Garden district frequently see their parcels are well configured for ADU builds. Communities around the Capitol Expressway corridor are seeing more homeowners add secondary units as housing demand rises. 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. Proximity to transit corridors can influence utility connection requirements for a given ADU project. Our team's knowledge of the San Jose permitting environment means smoother project delivery from kickoff through certificate of occupancy.
Book Your ADU Construction Assessment Today
If you're ready to move forward with ADU construction, Brother & Brother Builders is the team to call. Our builders provide licensed expertise in ADU construction for many different project types — from modest studio builds to large custom detached cottages. Our approach opens with a comprehensive site assessment where we learn what you're trying to accomplish and share clear expectations of what ADU construction on your property will look like.
Get in touch with our office to begin the conversation. No matter where you are in the decision-making process, our team is happy to walk through your options, review completed projects and help you take the next step. 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