Unlock New Space with Quality ADU Construction
Property owners throughout San Jose, CA are realizing that adding an accessory dwelling unit is one of the most rewarding investments they can make. ADU construction provides a flexible new living space on your existing property — whether you want to generate rental income. Brother & Brother Builders has guided hundreds of local homeowners see these visions to life with craftsmanship and care.
The interest in ADU construction has surged in recent years, and it's easy to understand why. California state law has simplified the process for homeowners to construct these secondary units, and local municipalities like San Jose have embraced the trend as a way to address housing needs. If you're planning a detached backyard cottage, a garage conversion, or an attached addition, ADU construction gives you more control over how your property works.
At Brother & Brother Builders, we bring years of hands-on experience to every ADU construction project. Our team knows the San Jose building codes, the engineering considerations, and the planning steps that make an ADU beautiful. When you're ready to explore what ADU construction could mean for your property, this guide covers 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 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 comes in multiple configurations, including detached backyard units, attached additions, garage conversions, and even below-grade dwelling units.
Mechanically, everything kicks off with a comprehensive review of your lot, where our professionals evaluate lot dimensions, existing structures, soil conditions, and local code requirements. From there, architectural drawings are prepared and submitted to the local building department. Once permits are secured, ADU construction enters the physical build phase — which encompasses site preparation, framing, HVAC, drywall, flooring, and exterior finishes. 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 level of craftsmanship at every stage. Products need to be chosen to align with the neighborhood's character. Systems like wiring and water supply must be sized for independent daily use. Brother & Brother Builders handles every ADU construction job with the same high standards we bring check here to full custom home projects.
Key Reasons to Choose ADU Construction
- Higher Resale Potential — ADU construction delivers real market value to your property, often returning more than the build cost when it's time to sell.
- Revenue Generation — A completed ADU is leasable as a long-term rental or short-term vacation unit, creating ongoing passive income for the homeowner.
- Space for Loved Ones — ADU construction provides adult children a self-contained residence without moving to another neighborhood.
- Design Flexibility — From two-bedroom configurations, ADU construction is adaptable to your specific needs.
- Simplified Regulatory Path — Recent state legislation has reduced the red tape associated with ADU construction, making the process that is faster and more cost-efficient than ever before.
- Responsible Property Development — Building an ADU uses your existing lot instead of consuming open land, which aligns with sustainability goals.
- Privacy for All Residents — Unlike a bedroom addition, ADU construction delivers a genuinely independent unit where tenants live autonomously.
- Durable Return on Investment — A well-built ADU holds its value for decades, providing both functional space and financial upside.
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 phase answers exactly what can be built before any resources go toward planning.
- Architectural Drafting and Space Planning — Our design team create comprehensive blueprints tailored to your needs. Every square foot is planned to optimize daily use.
- Permitting and City Approval — 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 issued, the build starts. This includes grading the site, completing foundation work, and running initial plumbing and electrical conduits.
- Framing, Roofing, and Exterior Work — The structural frame is erected followed by roofing, siding, windows, and exterior doors. This phase, the ADU becomes recognizable as a structure.
- MEP Systems Rough-In — Licensed subcontractors install the heating, cooling, drainage, and power infrastructure that make the ADU ready for occupancy. All work is inspected at each code checkpoint throughout ADU construction.
- Interior Finishing and Final Inspections — Flooring, cabinetry, fixtures, paint are fitted and completed to your specifications. A last official inspection grants legal occupancy status and your new space is cleared for use.
Who Is a Strong Candidate for ADU Construction?
People who see the greatest return from ADU construction typically fall into a few common profiles. If you own a single-family home with enough lot space to meet setback requirements, you're already well-positioned. Homeowners hoping to offset mortgage costs through rental are among the most common ADU construction clients, along with families supporting elderly parents.
Another strong candidate is someone who works from home and wants a separate office or studio space that doesn't interfere with your family's daily life. Landlords and real estate investors who want to maximize their land are also a natural fit for ADU construction, since the long-term value is proven.
Homeowners who may want to pause and evaluate include sites with unusual utility access challenges. Parcels in historic districts or HOA-restricted communities may need a modified approach. Brother & Brother Builders reviews each property case by case to provide realistic options.
ADU Construction Common Questions Answered
How long does ADU construction generally take from start to finish?
The full timeline for ADU construction typically ranges from six to fourteen months, based on the project scope and local permitting timelines. City review on its own can take a significant portion of the overall timeline in San Jose, so planning ahead matters. Smaller detached units may complete more quickly, while larger new construction ADUs require more time.
What does ADU construction usually run in terms of budget?
Pricing depends on many factors based on project complexity and finishes selected. Locally, ADU construction typically ranges from $150,000 to $400,000 or more for a fully custom construction. Interior conversion projects are generally priced lower, sometimes starting around $80,000 depending on scope. A detailed estimate can only be developed after a thorough property review.
Is ADU construction disruptive 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 generally the least intrusive, since the crew operates at a distance from your living areas. Interior conversions may require temporary access during key milestones. We provide advance notice about upcoming work and timelines.
Do I need to move out during ADU construction?
In most cases, you won't have to vacate your main home during ADU construction. Most job sites are set up to let you stay in your primary unit throughout the construction timeline. Exceptions may arise if interior conversion work touches shared systems in ways that temporarily impact livability. The team at Brother & Brother Builders will discuss these scenarios during the pre-construction consultation.
How long will an ADU built through professional ADU construction hold up?
An ADU constructed with quality materials can be expected to last as long as any standard residential structure — often several decades with routine maintenance. Longevity is tied to the standard of construction, how well routine maintenance is performed, and whether systems like roofing and plumbing are serviced regularly. Brother & Brother Builders specifies commercial-grade materials and follow all code requirements to protect your investment for the long haul.
ADU Construction for San Jose Homeowners
The communities throughout San Jose provide a wide range of property types that are perfectly suited for ADU construction. Residents in the Rose Garden district have found their lots accommodate detached backyard units nicely. The Berryessa area are increasingly popular for ADU construction as families expand. Whether your property is near downtown San Jose, our team has project experience in the area.
Local regulatory bodies in this area applies particular standards for ADU construction that experienced builders know well. Location near major arterials like Story Road or Tully Road can influence utility connection requirements for a given ADU project. Brother & Brother Builders' experience across this region's building landscape means fewer surprises from the first meeting to the final inspection.
Start Your ADU Construction Assessment Today
Should you be thinking about how to move forward with ADU construction, Brother & Brother Builders is here to help. Our experts offer licensed expertise in ADU construction for many different project types — from modest studio builds to fully independent secondary homes. The process begins with a comprehensive site assessment 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. Whether you're in the early stages of planning, we're glad to answer questions, share examples of our work and make sure you feel confident before committing. This type of project is a meaningful commitment — and we're committed to helping you get it right.
Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632