Expand Your Home with Expert ADU Construction
Homeowners across San Jose, CA are discovering that adding an accessory dwelling unit is one of the most practical investments they can make. ADU construction creates a versatile 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 care.
The popularity of 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 supported the trend as a way to address housing needs. Whether you want to build a detached backyard cottage, a garage conversion, or an attached addition, ADU construction provides increased control over how your property functions.
At Brother & Brother Builders, we apply deep hands-on experience to every ADU construction project. Our team understands the local permitting process, the engineering details, and the design choices that make an ADU beautiful. When you're ready to explore 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 involves 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 — equipped with a kitchen, bathroom, sleeping area, and its own entryway — that exists on the same lot as a primary click here 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 detailed site assessment, where our builders evaluate setbacks, zoning, utility access, and structural feasibility. From there, design plans are prepared and submitted to the city for permit approval. Once the paperwork is cleared, ADU construction moves into the physical build phase — which encompasses site preparation, framing, HVAC, drywall, flooring, and exterior finishes. The result is a move-in-ready living unit adjacent to or detached from your main home.
The difference between a good and a great ADU build is the depth of planning 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 handles every ADU construction job with the same high standards we use on major custom home projects.
Key Benefits ADU Construction
- Higher Resale Potential — ADU construction delivers real market value to your property, often generating strong equity gains 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 comfortable home of their own without leaving the property.
- Customization Options — 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 barriers and delays associated with ADU construction, making the process that is faster and more cost-efficient than ever before.
- Sustainable Land Use — Building an ADU uses your existing lot instead of expanding urban sprawl, which supports broader sustainability goals.
- Separate Entrances and Spaces — Unlike a bedroom addition, ADU construction produces a fully self-contained unit where residents have their own space.
- Durable Return on Investment — A well-built ADU remains an asset for the long haul by offering both livable square footage and monetary benefit.
The ADU Construction Procedure Step by Step
- Property Walkthrough and Feasibility Check — Our experts review your property to evaluate setbacks, lot coverage limits, and utility connections. This phase answers exactly what ADU types will work before any resources go toward planning.
- Custom Design and Architectural Planning — Experienced draftspeople create comprehensive blueprints 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 approved, physical construction begins. This includes grading the site, laying the structural base, and establishing utility connections.
- Structural Framing and Weatherproofing — Walls and roof systems go up followed by weatherproofing and exterior finish materials. At this stage, the ADU becomes recognizable as a structure.
- MEP Systems Rough-In — Certified technicians 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 — Countertops, hardware, finishes, and fixtures are fitted and completed to the agreed design. A last official inspection grants legal occupancy status and your new space is cleared for use.
Who Is a Good Candidate for ADU Construction?
Property owners who are best suited from ADU construction generally fit within 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 hoping to offset mortgage costs through rental are among the most motivated ADU construction clients, along with families accommodating adult children who need housing.
ADU construction also suits someone who works from home and wants a private work environment that remains away 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 properties with significant setback limitations. Parcels in historic districts or HOA-restricted communities may require additional review. Brother & Brother Builders reviews each property on its own merits to recommend the right path forward.
ADU Construction Common Questions Answered
How long does ADU construction typically take from start to finish?
The total process for ADU construction typically ranges from six to fourteen months, depending on design complexity and city review schedules. The approval phase alone can take several months in San Jose, so beginning the process sooner rather than later is wise. Simpler garage conversions often finish in the lower end of the range, while larger new construction ADUs take longer to complete.
What does ADU construction cost in San Jose?
Costs vary widely 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. Attached ADU additions often come in under, sometimes in the $80,000 to $150,000 range. A detailed estimate can only be produced following a thorough property review.
Is ADU construction difficult to live through while it's underway?
The day-to-day impact depends on where the ADU is being built. New construction in the rear yard are usually easier to live alongside, since the crew operates at a distance from your living areas. Garage conversions or attached additions may involve some shared wall work during certain phases of construction. We provide advance notice about upcoming work and timelines.
Do I need to leave my home during ADU construction?
In most cases, you are not required to vacate your house during ADU construction. Most builds are designed so that you remain on the property throughout the process. Exceptions may arise if significant structural connections require temporary shutoffs in ways that require short-term access disruption. Our construction supervisors will flag these situations during the planning phase.
How long will an ADU built through professional ADU construction hold up?
Any ADU built to code with professional oversight can be expected to last as long as the main residence — often several decades with routine maintenance. Longevity is tied to the standard of construction, how consistently minor repairs are addressed, and whether systems like roofing and plumbing are serviced regularly. We select residential-grade products rated for longevity and follow all code requirements to ensure lasting performance.
ADU Construction for San Jose Homeowners
San Jose's neighborhoods offer a variety of property types that are perfectly suited for ADU construction. Property owners near the Almaden Valley area often discover their properties accommodate detached backyard units nicely. Neighborhoods near Blossom Hill Road have seen growing ADU activity as housing demand rises. Whether your property is near downtown San Jose, our team has project experience in the area.
The City of San Jose's building department applies particular standards for ADU construction that our team navigates routinely. Location near major arterials like Story Road or Tully Road can affect how quickly permits are approved for a given ADU project. Our familiarity with these local conditions means fewer surprises from kickoff through certificate of occupancy.
Schedule Your ADU Construction Consultation Today
When you want to add an ADU to your property, Brother & Brother Builders is here to help. Our experts offer years of hands-on experience in ADU construction across a wide range of project types — from small attached additions to multi-room backyard residences. Our approach opens with a thorough and honest property review where we learn what you're trying to accomplish and give you a realistic picture of what ADU construction on your property will look like.
Get in touch with our office to schedule a site visit. Even if you're just exploring the idea, we're glad to discuss timelines, costs, and design possibilities and help you take the next step. Building an ADU is a major decision — and we're committed to helping you get it right.
Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632