Unlock New Space with Quality ADU Construction
Families in San Jose, CA are discovering that adding an accessory dwelling unit is one of the most practical 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 helped hundreds of local homeowners turn these plans to life with craftsmanship and integrity.
The popularity of ADU construction has grown rapidly 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 embraced the trend as a way to increase density responsibly. Whether you want to build a detached backyard cottage, a garage conversion, or an attached addition, ADU construction gives you more control over how your property functions.
At Brother & Brother Builders, we draw on extensive hands-on experience to check here every ADU construction job. Our team is familiar with city and county requirements, the engineering considerations, and the aesthetic decisions that make an ADU functional. When you're ready to explore what ADU construction could look like on your property, this guide explains everything you need to know.
What Is the ADU Construction Process?
ADU construction refers to the process of engineering, filing for, and completing an accessory dwelling unit on a residential property. An accessory dwelling unit is a complete living space — including a kitchen, bathroom, sleeping area, and its own entrance — that is located on the same parcel as a primary residence. ADU construction comes in multiple configurations, 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 builders evaluate lot dimensions, existing structures, soil conditions, and local code requirements. From there, architectural drawings are prepared and submitted to the relevant municipal authority. Once the paperwork is cleared, ADU construction moves into the physical build phase — which includes foundation work, framing, mechanical systems, weatherproofing, and interior finishing. 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 depth of planning at every stage. Materials must be selected to align with the neighborhood's character. Systems like HVAC and drainage must be built for long-term residential demand. Brother & Brother Builders treats each project with the same professional rigor we use on major custom home projects.
Key Benefits 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 can be rented as a long-term rental or short-term vacation unit, generating steady monthly revenue for the homeowner.
- Space for Loved Ones — ADU construction offers family members a self-contained residence without losing proximity to the family.
- Design Flexibility — From modern studio layouts, ADU construction may be customized to the intended occupant's lifestyle.
- Streamlined Approval Process — Recent state legislation has minimized the red tape associated with ADU construction, making the process that is faster and more cost-efficient than ever before.
- Efficient Use of Your Lot — Building an ADU works within your current footprint instead of expanding urban sprawl, which aligns with sustainability goals.
- Separate Entrances and Spaces — Unlike a bedroom addition, ADU construction creates a truly separate unit where residents have their own space.
- Lasting Financial Benefit — A well-built ADU remains an asset for decades, providing both functional space and financial upside.
The ADU Construction Journey Step by Step
- Property Walkthrough and Feasibility Check — Our experts review your property to determine what type of ADU is allowed and where it can be placed. This phase answers exactly what ADU types will work before any time is invested in drawings.
- Architectural Drafting and Space Planning — Licensed architects and designers create precise architectural drawings based on your goals. 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. Our team handles all submissions on your behalf, resolving any revision requests promptly.
- Ground Prep and Structural Base — Once permits are granted, physical construction begins. This includes grading the site, completing foundation work, and setting up utilities.
- Structural Framing and Weatherproofing — Framing is completed followed by roofing, siding, windows, and exterior doors. This phase, the ADU becomes recognizable as a structure.
- MEP Systems Rough-In — Skilled tradespeople install the plumbing lines, electrical wiring, and HVAC systems that make the ADU ready for occupancy. All work is inspected at designated stages throughout ADU construction.
- Interior Completion and City Sign-Off — Flooring, cabinetry, fixtures, paint are placed and inspected to your specifications. A last official inspection confirms the unit is code-compliant and the ADU is ready for use.
Who Is a Strong Candidate for ADU Construction?
Property owners who are best suited from ADU construction often belong to a few common profiles. If you have a residential property with available square footage under zoning rules, you're already a strong candidate. Homeowners wanting to add a revenue stream through rental are among the most common ADU construction clients, along with families navigating multigenerational living situations.
You may also be 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 well suited for ADU construction, since the return on investment is well-documented.
Homeowners who may want to pause and evaluate include properties with significant setback limitations. Very small lots or properties with easements may face additional constraints. 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 typically take from start to finish?
The full timeline for ADU construction commonly spans six to fourteen months, based on the project scope and city review schedules. City review on its own can take several months in San Jose, so beginning the process sooner rather than later is wise. Straightforward interior conversions can move faster, while larger new construction ADUs require more time.
What does ADU construction usually run in terms of budget?
Budget requirements differ based on project complexity and finishes selected. In the San Jose area, ADU construction typically ranges from $150,000 to $400,000 or more for a standalone backyard unit. Interior conversion projects often come in under, sometimes in the $80,000 to $150,000 range. A precise cost projection can only be given after completing a formal feasibility evaluation.
Is ADU construction difficult to live through while it's underway?
The level of disruption depends on the project's location on your property. Standalone ADU projects are typically less disruptive, since the crew operates at a distance from your living areas. Interior conversions may create short-term inconveniences during specific stages like framing or MEP rough-in. We provide advance notice about what to expect at each stage.
Do I need to vacate the property during ADU construction?
In most cases, you do not need to vacate your main home during ADU construction. Most job sites are structured to allow you remain on the property throughout the construction timeline. Certain situations could require a brief departure if significant structural connections require temporary shutoffs in ways that briefly affect habitability. Our construction supervisors will walk you through any potential disruptions during the kickoff meeting.
How long will an ADU built through professional ADU construction remain in good condition?
A well-built ADU should last as long as any standard residential structure — indefinitely with proper upkeep. Longevity is tied to the systems installed, whether the unit is properly cared for, and how proactively issues are resolved over time. Brother & Brother Builders specifies high-quality components and build to current California residential standards to deliver a structure that stands the test of time.
ADU Construction for Local 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 have found their lots are well configured for ADU builds. Communities around the Capitol Expressway corridor are increasingly popular for ADU construction as housing demand rises. Whether your property is near downtown San Jose, our team knows the permitting landscape well.
San Jose's permitting office follows defined procedures for ADU construction that require a builder familiar with local expectations. Proximity to transit corridors can influence utility connection requirements for a given ADU project. Our familiarity with these local conditions means more accurate timelines and budgets from the first meeting to the final inspection.
Start Your ADU Construction Planning Session Today
If you're ready to move forward with ADU construction, Brother & Brother Builders is ready to guide you. Our builders provide years of hands-on experience in ADU construction including all types of project types — from simple garage conversions to multi-room backyard residences. Every project starts with a detailed, no-pressure consultation where we listen to your goals and share clear expectations of what ADU construction on your property will look like.
Get in touch with our office to set up your consultation. Whether you're in the early stages of planning, we're glad to walk through your options, review completed projects and give you the clarity you need to move forward. This type of project is a meaningful commitment — 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