Transform Your Property with Expert ADU Construction
Property owners throughout San Jose, CA are realizing that adding an accessory dwelling unit is one of the most practical 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 turn these plans to life with precision and integrity.
The demand for ADU construction has grown rapidly in recent years, and it's no mystery. California state law has simplified the process for homeowners to build these secondary units, and local municipalities like San Jose have embraced 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 works.
At Brother & Brother Builders, we draw on extensive hands-on experience to every ADU construction job. Our team understands the local permitting process, the engineering requirements, and the design choices that make an ADU functional. When you're ready to explore what ADU construction could mean for your property, this guide explains everything you need to know.
What Is ADU Construction?
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 self-contained living space — equipped with a kitchen, bathroom, sleeping area, and its own entryway — that is located on the same parcel 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, everything kicks off with a detailed site assessment, where our builders evaluate setbacks, zoning, utility access, and structural feasibility. 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 encompasses site preparation, framing, roofing, plumbing, electrical, insulation. The result is a fully functional living unit connected to or independent of your main home.
What sets quality ADU construction apart is the level of craftsmanship at every stage. Products need to be chosen to complement the existing structure. Systems like wiring and water supply must be built for long-term residential demand. Brother & Brother Builders treats each project with the same technical discipline we bring to full custom home projects.
Key Reasons to Choose ADU Construction
- Increased Property Value — ADU construction adds measurable market value to your property, often generating strong equity gains 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.
- Housing for Extended Family — ADU construction provides adult children a private, independent living space without moving to another neighborhood.
- Personalized Layouts — From open-plan one-bedrooms, ADU construction may be customized to your specific needs.
- Simplified Regulatory Path — Recent state legislation has reduced the red tape associated with ADU construction, resulting in a timeline that is faster and less expensive than ever before.
- Efficient Use of Your Lot — Building an ADU maximizes the land you already own instead of expanding urban sprawl, which contributes to sustainability goals.
- Independent Living Areas — Unlike a bedroom addition, ADU construction delivers a genuinely independent unit where occupants have full privacy.
- 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 Journey Step by Step
- Initial Property Assessment and Feasibility Review — Our builders assess your property to analyze zoning rules, slope conditions, and available square footage. This stage clarifies exactly what ADU types will work before any resources go toward planning.
- Custom Design and Architectural Planning — Licensed architects and designers create precise architectural drawings reflecting your priorities. Space is thoughtfully allocated to optimize daily use.
- Permit Submission and Municipal Review — ADU construction in San Jose requires submitting plans to the city's building department for sign-off and verification. Our team handles all submissions on your behalf, responding to review feedback promptly.
- Ground Prep and Structural Base — Once permits are issued, 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.
- Interior Systems and Infrastructure — Licensed subcontractors 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 fitted and completed to your specifications. A closing municipal review grants legal occupancy status and the ADU is ready for use.
Who Is a Right Fit for ADU Construction?
People who see the greatest return from ADU construction often belong to a few recognizable groups. If you own a single-family home with available square footage under zoning rules, you're already in a good starting place. Homeowners hoping to offset mortgage costs through rental are among the most common ADU construction clients, along with families accommodating adult children who need housing.
You may also be someone who needs a dedicated professional workspace and wants a separate office or studio space that is distinct from your family's daily life. Landlords and real estate investors who already own residential properties are also a natural fit for ADU construction, since rental income frequently offsets build costs.
Homeowners who may want to pause and evaluate include lots that are below minimum size thresholds. Sites with underground infrastructure conflicts may face additional constraints. Our experts will evaluate each property case by case to recommend the right path forward.
ADU Construction Frequently Asked Questions
How long does ADU construction typically take from start to finish?
The complete duration for ADU construction usually runs between six to fourteen months, depending on design complexity and local permitting timelines. Permitting alone can take a significant portion of the overall timeline in San Jose, so starting early is important. Smaller detached units often finish in the lower end of the range, while custom detached builds require more time.
What does ADU construction typically cost?
Costs vary widely based on the type and size of the ADU. Locally, 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 starting around $80,000 depending on scope. An accurate budget can only be developed after a thorough property review.
Is ADU construction intrusive while it's underway?
The day-to-day impact depends on whether you're converting existing space or building new. Detached backyard builds are usually easier to live alongside, since the crew operates at a distance from your living areas. Projects that connect to the main structure may create short-term inconveniences during key milestones. 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 house during ADU construction. The vast majority of projects are set up to let you continue living in the home throughout the build. Certain situations could require a brief departure if major utility upgrades affect the main house in ways that temporarily impact livability. Our project managers will discuss these scenarios during the kickoff meeting.
How long will an ADU built through professional ADU construction last?
A well-built ADU should last as long as the main residence — typically 50 years or more. How long it lasts comes down to the standard of construction, whether the unit is properly cared for, and if mechanical components are maintained on schedule. Brother & Brother Builders specifies high-quality components and build to current California residential standards to ensure lasting performance.
ADU Construction for San Jose Homeowners
San Jose's neighborhoods offer a variety of property types that are well suited for ADU construction. Property owners near the Almaden Valley area frequently see their parcels work well for both attached and detached projects. The Berryessa area are seeing more homeowners add secondary units as housing demand rises. From neighborhoods near the Guadalupe River Park corridor to those near Branham Lane, our team has likely worked nearby.
Local regulatory bodies in this area follows defined procedures for ADU construction that experienced builders know well. Location near major arterials check here like Story Road or Tully Road can impact the design approach for a given ADU project. Our familiarity with this region's building landscape means fewer surprises from design through the final walkthrough.
Schedule Your ADU Construction Assessment Today
When you want to move forward with ADU construction, Brother & Brother Builders is here to help. Our builders provide proven skills in ADU construction for many different project types — from small attached additions to multi-room backyard residences. Our approach opens with a thorough and honest property review where we listen to your goals and share clear expectations of what the project will involve.
Reach out to our team to begin the conversation. Whether you're in the early stages of planning, our team is happy to 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