Expand Your Home 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 helped hundreds of local homeowners bring these projects to life with precision and integrity.
The popularity of ADU construction has grown rapidly in recent years, and it's easy to understand why. California state law now makes it easier for homeowners to build 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 gives you more control over how your property functions.
At Brother & Brother Builders, we draw on extensive hands-on experience to every ADU construction project. Our team is familiar with city and county requirements, the engineering requirements, and the aesthetic decisions that make an ADU truly livable. Should you want to learn about what ADU construction could look like on your property, this guide will walk you through 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 — featuring a kitchen, bathroom, sleeping area, and its own entrance — 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 basement or interior conversions.
Mechanically, everything kicks off with a detailed site assessment, where our team evaluate lot dimensions, existing structures, soil conditions, and local code requirements. From there, architectural drawings are prepared and submitted to the city for permit approval. Once permits are secured, ADU construction enters the physical build phase — which covers everything from foundational work, framing, roofing, plumbing, electrical, insulation. The result is a move-in-ready living unit connected to or independent of your main home.
What sets quality ADU construction apart is the attention to detail at every stage. Materials must be selected to match the primary home's aesthetic. Systems like HVAC and drainage must be sized for independent daily use. Brother & Brother Builders treats each project with the same high standards we apply to large-scale custom home projects.
Key Advantages 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.
- Monthly Cash Flow — A completed ADU can be rented as a long-term rental or short-term vacation unit, generating steady monthly revenue for the homeowner.
- Multi-Generational Living — ADU construction offers family members a comfortable home of their own without losing proximity to the family.
- Design Flexibility — From two-bedroom configurations, ADU construction can be tailored to the intended occupant's lifestyle.
- Faster Permitting in California — Recent state legislation has reduced the permitting obstacles associated with ADU construction, resulting in a timeline that is faster and more affordable than ever before.
- Responsible Property Development — Building an ADU works within your current footprint instead of consuming open land, which supports broader sustainability goals.
- Separate Entrances and Spaces — Unlike a bedroom addition, ADU construction produces a fully self-contained unit where occupants have full privacy.
- Durable Return on Investment — A well-built ADU holds its value for the long haul by offering both livable square footage and monetary benefit.
The ADU Construction Journey Step by Step
- Site Evaluation and Zoning Analysis — Our experts review 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 — Our design team create comprehensive blueprints tailored to your needs. Space is thoughtfully allocated to maximize function and livability.
- Filing for Building Permits — ADU construction in San Jose involves filing drawings to the city's building department for sign-off and verification. Brother & Brother Builders coordinates the permitting on your behalf, resolving any revision requests promptly.
- Excavation and Foundation Installation — Once permits are granted, on-site work kicks off. This involves leveling and prepping the ground, laying the structural base, and running initial plumbing and electrical conduits.
- Framing, Roofing, and Exterior Work — The structural frame is erected followed by weatherproofing and exterior finish materials. During this step, the ADU transforms from a concept to a building.
- Interior Systems and Infrastructure — Licensed subcontractors install the heating, cooling, drainage, and power infrastructure that make the ADU ready for occupancy. Inspections are completed at designated stages throughout ADU construction.
- Finishes, Fixtures, and Final Walkthrough — Trim, appliances, tile, and lighting are installed and finished to the agreed design. A final city inspection confirms the unit is code-compliant 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 often belong to a few clear categories. If you have a residential property 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 motivated ADU construction clients, along with families navigating multigenerational living situations.
You may also be someone who works from home and wants a separate office or studio space that doesn't interfere with your family's daily life. Real estate-minded homeowners who are building a portfolio are also a natural fit for ADU construction, since rental income frequently offsets build costs.
Homeowners who may want to pause and evaluate include sites with unusual utility access challenges. Sites with underground infrastructure conflicts may face additional constraints. Our team can assess each property case by case to provide realistic get more info options.
ADU Construction FAQ
How long does ADU construction usually take from start to finish?
The total process for ADU construction typically ranges from six to fourteen months, influenced by the type of unit being built and how quickly approvals come through. City review on its own can take two to four months in San Jose, so beginning the process sooner rather than later is wise. Smaller detached units can move faster, while multi-room detached cottages take longer to complete.
What does ADU construction typically cost?
Budget requirements differ based on the type and size of the ADU. In the San Jose area, ADU construction typically ranges from $150,000 to $400,000 or more for a standalone backyard unit. Garage conversions tend to cost less, sometimes starting around $80,000 depending on scope. A detailed estimate 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. Standalone ADU projects are typically less disruptive, since work happens away from the main house. Projects that connect to the main structure may create short-term inconveniences during key milestones. Brother & Brother Builders keeps you informed about any phases that may affect your routine.
Do I need to move out during ADU construction?
In most cases, you do not need to vacate your main home during ADU construction. Most builds are structured to allow you stay in your primary unit throughout the process. There are edge cases if major utility upgrades affect the main house in ways that briefly affect habitability. The team at Brother & Brother Builders will discuss these scenarios during the planning phase.
How long will an ADU built through professional ADU construction last?
Any ADU built to code with professional oversight should last as long as any standard residential structure — often several decades with routine maintenance. Longevity is tied to the quality of materials used, how well routine maintenance is performed, and how proactively issues are resolved over time. We select 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 San Jose Homeowners
The communities throughout San Jose provide a diverse mix of property types that are well suited for ADU construction. Property owners near the Almaden Valley area have found their lots accommodate detached backyard units nicely. Communities around the Capitol Expressway corridor have seen growing ADU activity as housing demand rises. If you're located closer to Evergreen, our team has likely worked nearby.
Local regulatory bodies in this area has developed specific protocols for ADU construction that experienced builders know well. 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 Assessment Today
When you want to move forward with ADU construction, Brother & Brother Builders is here to help. We bring years of hands-on experience in ADU construction for many different project types — from simple garage conversions to multi-room backyard residences. The process begins with a thorough and honest property review where we listen to your goals and provide an honest assessment of what ADU construction on your property will look like.
Reach out to our team to set up your consultation. Even if you're just exploring the idea, we enjoy walk through your options, review completed projects and give you the clarity you need to move forward. ADU construction is a significant investment — and we're committed to helping you get it right.
Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632