Transform Your Property with Quality ADU Construction
Homeowners across San Jose, CA are discovering that adding an accessory dwelling unit is one of the most rewarding 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 care.
The demand for ADU construction has surged in recent years, and it's easy to understand why. California state law now makes it easier for homeowners to construct these secondary units, and local municipalities like San Jose have encouraged 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 gives you more control over how your property works.
At Brother & Brother Builders, we apply deep hands-on experience to every ADU construction job. Our team is familiar with city and county requirements, the engineering details, and the planning steps that make an ADU truly livable. Should you want to learn about what ADU construction could do for your property, this guide covers everything you need to know.
What Is the ADU Construction Process?
ADU construction involves the process of engineering, filing for, and completing an accessory dwelling read more 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 comes in multiple configurations, including detached backyard units, attached additions, garage conversions, and even interior space reconfigurations.
Mechanically, everything kicks off with a thorough property evaluation, where our professionals evaluate property boundaries, available square footage, and infrastructure capacity. From there, blueprints are prepared and submitted to the relevant municipal authority. Once permits are secured, ADU construction enters the physical build phase — which covers everything from foundational work, framing, HVAC, drywall, flooring, and exterior finishes. The result is a completely finished living unit attached to or separate from your main home.
What separates excellent ADU construction from an average project is the attention to detail at every stage. Products need to be chosen to complement the existing structure. Systems like wiring and water supply must be designed to handle full-time occupancy. Brother & Brother Builders treats each project with the same technical discipline we use on major custom home projects.
Key Reasons to Choose ADU Construction
- Boosted Home Equity — 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, providing a consistent income stream for the homeowner.
- Space for Loved Ones — ADU construction offers family members a self-contained residence without moving to another neighborhood.
- Design Flexibility — From modern studio layouts, ADU construction may be customized to your household's priorities.
- Faster Permitting in California — Recent state legislation has minimized the permitting obstacles 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 uses your existing lot instead of consuming open land, which aligns with sustainability goals.
- Independent Living Areas — Unlike a bedroom addition, ADU construction produces a fully self-contained unit where residents have their own space.
- Long-Term Investment Security — A well-built ADU holds its value for the long haul by offering both livable square footage and monetary benefit.
The ADU Construction Process Step by Step
- Initial Property Assessment and Feasibility Review — Our team visits your property to determine what type of ADU is allowed and where it can be placed. This step tells you exactly what ADU types will work before any money is spent on design.
- Custom Design and Architectural Planning — Licensed architects and designers create detailed floor plans based on your goals. Space is thoughtfully allocated to optimize daily use.
- Permitting and City Approval — ADU construction in San Jose requires submitting plans to the city's building department for review and approval. Our team handles all submissions on your behalf, addressing any city comments promptly.
- Excavation and Foundation Installation — Once permits are approved, the build starts. This involves leveling and prepping the ground, pouring the concrete foundation, and establishing utility connections.
- Framing, Roofing, and Exterior Work — The structural frame is erected followed by roofing, siding, windows, and exterior doors. At this stage, the ADU transforms from a concept to a building.
- 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 required milestones throughout ADU construction.
- Finishes, Fixtures, and Final Walkthrough — Countertops, hardware, finishes, and fixtures are fitted and completed to the agreed design. A last official inspection confirms the unit is code-compliant and your new space is cleared for use.
Who Is a Good Candidate for ADU Construction?
People who see the greatest return from ADU construction typically fall into a few clear categories. If you are a homeowner with a backyard, garage, or basement that could be converted, 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.
You may also be someone who runs a small business and wants a separate office or studio space that doesn't interfere with your family's daily life. Property investors and rental owners who already own residential properties are also prime candidates for ADU construction, since rental income frequently offsets build costs.
Those who should discuss alternatives first include properties with significant setback limitations. Sites with underground infrastructure conflicts may face additional constraints. Our team can assess each property on its own merits to provide realistic options.
ADU Construction FAQ
How long does ADU construction typically take from start to finish?
The total process for ADU construction commonly spans six to fourteen months, based on the project scope and local permitting timelines. The approval phase alone can take two to four months in San Jose, so planning ahead matters. Simpler garage conversions may complete more quickly, while multi-room detached cottages take longer to complete.
What does ADU construction typically cost?
Pricing depends on many factors based on whether it's a conversion or new construction. For most projects in this region, ADU construction generally falls between $150,000 to $400,000 or more for a fully custom construction. Garage conversions are generally priced lower, 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 day-to-day impact depends on whether you're converting existing space or building new. Detached backyard builds are generally the least intrusive, since work happens away from the main house. Interior conversions may require temporary access during specific stages like framing or MEP rough-in. Brother & Brother Builders keeps you informed about any phases that may affect your routine.
Do I need to vacate the property during ADU construction?
For the majority of homeowners, you won't have to vacate your house during ADU construction. Most builds are designed so that you stay in your primary unit throughout the construction timeline. There are edge cases if significant structural connections require temporary shutoffs in ways that require short-term access disruption. Our project managers will discuss these scenarios during the pre-construction consultation.
How long will an ADU built through professional ADU construction last?
An ADU constructed with quality materials should last as long as the main residence — typically 50 years or more. Durability depends to the standard of construction, how consistently minor repairs are addressed, and how proactively issues are resolved over time. Our builds use high-quality components and build to current California residential standards to ensure lasting performance.
ADU Construction for Local Homeowners
The communities throughout San Jose provide a wide range of property types that are ideally positioned for ADU construction. Homeowners in the Willow Glen neighborhood frequently see their parcels work well for both attached and detached projects. Neighborhoods near Blossom Hill Road have seen growing ADU activity as families expand. From neighborhoods near the Guadalupe River Park corridor to those near Branham Lane, our team has project experience in the area.
The City of San Jose's building department applies particular standards for ADU construction that require a builder familiar with local expectations. Location near major arterials like Story Road or Tully Road can affect how quickly permits are approved for a given ADU project. Brother & Brother Builders' experience across the San Jose permitting environment means smoother project delivery from the first meeting to the final inspection.
Start Your ADU Construction Assessment Today
If you're ready to explore what an ADU could look like on your lot, Brother & Brother Builders is the team to call. We bring licensed expertise in ADU construction including all types of project types — from small attached additions to multi-room backyard residences. Our approach opens with a detailed, no-pressure consultation where we understand your vision and provide an honest assessment of what's achievable.
Get in touch with our office to schedule a site visit. Even if you're just exploring the idea, we enjoy answer questions, share examples of our work and make sure you feel confident before committing. This type of project is a meaningful commitment — and our goal is to ensure it delivers real value.
Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632