Brother & Brother Builders

Transform Your Property with Quality ADU Construction

Property owners throughout San Jose, CA are finding that adding an accessory dwelling unit is one of the most practical investments they can make. ADU construction opens the door to a versatile new living space on your existing property — whether you want to house a family member. Brother & Brother Builders has supported hundreds of local homeowners bring these projects to life with skill and care.

The demand for ADU construction has increased significantly in recent years, and it's no mystery. California state law has simplified the process for homeowners to add these secondary units, and local municipalities like San Jose have encouraged 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 works.

At Brother & Brother Builders, we apply deep hands-on experience to every ADU construction build. Our team knows the San Jose building codes, the engineering details, and the design choices that make an ADU beautiful. Should you want to learn about what ADU construction could do for your property, this guide covers everything you need to know.

What Is an ADU Build?

ADU construction describes the process of engineering, filing for, and completing an accessory dwelling unit on a residential property. An accessory dwelling unit is a fully independent living space — featuring a kitchen, bathroom, sleeping area, and its own access point — that exists on the same lot as a primary residence. ADU construction can take several forms, 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 professionals evaluate property boundaries, available square footage, and infrastructure capacity. From there, architectural drawings are prepared and submitted to the relevant municipal authority. Once permits are secured, ADU construction transitions to the physical build phase — which includes foundation work, framing, mechanical systems, adu construction near San Jose weatherproofing, and interior finishing. The result is a fully functional living unit adjacent to or detached from your main home.

What separates excellent ADU construction from an average project is the attention to detail at every stage. Components should be specified to match the primary home's aesthetic. Systems like wiring and water supply must be sized for independent daily use. Brother & Brother Builders handles every ADU construction job with the same professional rigor we apply to large-scale custom home projects.

Key Advantages ADU Construction

• Boosted Home Equity — ADU construction adds measurable market value to your property, often generating strong equity gains when it's time to sell.
• Monthly Cash Flow — 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 leaving the property.
• Personalized Layouts — From modern studio layouts, ADU construction may be customized to your specific needs.
• Faster Permitting in California — Recent state legislation has minimized the barriers and delays associated with ADU construction, creating a path that is faster and more affordable than ever before.
• Responsible Property Development — Building an ADU uses your existing lot instead of requiring new development, which contributes to sustainability goals.
• Privacy for All Residents — 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 many years and generates both functional space and financial upside.

The ADU Construction Procedure Step by Step

1. Initial Property Assessment and Feasibility Review — Our builders assess your property to determine what type of ADU is allowed and where it can be placed. This step tells you exactly what's possible before any time is invested in drawings.
2. Custom Design and Architectural Planning — Our design team create precise architectural drawings based on your goals. Space is thoughtfully allocated to maximize function and livability.
3. Permitting and City Approval — 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, responding to review feedback promptly.
4. Ground Prep and Structural Base — Once permits are approved, on-site work kicks off. This involves leveling and prepping the ground, laying the structural base, and establishing utility connections.
5. Framing, Roofing, and Exterior Work — Framing is completed followed by roofing, siding, windows, and exterior doors. During this step, the ADU takes its visible shape.
6. Interior Systems and Infrastructure — Skilled tradespeople install the water supply, drain lines, and electrical panel that make the ADU ready for occupancy. Every system is reviewed at designated stages throughout ADU construction.
7. Interior Completion and City Sign-Off — Trim, appliances, tile, and lighting are fitted and completed to the approved plan. A closing municipal review issues the certificate of occupancy and your new space is cleared for use.

Who Is a Strong Candidate for ADU Construction?

Property owners who are best suited from ADU construction generally fit within a few common profiles. If you own a single-family home with a backyard, garage, or basement that could be converted, you're already a strong candidate. Homeowners wanting to add a revenue stream through rental are among the most motivated ADU construction clients, along with families supporting elderly parents.

ADU construction also suits someone who needs a dedicated professional workspace and wants a separate office or studio space that doesn't interfere with your family's daily life. Landlords and real estate investors who are building a portfolio are also a natural fit for ADU construction, since the return on investment is well-documented.

Those who should discuss alternatives first include sites with unusual utility access challenges. Parcels in historic districts or HOA-restricted communities may need a modified approach. Our experts will evaluate each property case by case to advise you on what's feasible.

ADU Construction FAQ

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 city review schedules. The approval phase alone can take a significant portion of the overall timeline in San Jose, so planning ahead matters. Simpler garage conversions can move faster, while custom detached builds fall toward the upper end of the timeline.

What does ADU construction usually run in terms of budget?

Pricing depends on many factors based on the type and size of the ADU. For most projects in this region, ADU construction typically ranges from $150,000 to $400,000 or more for a detached new build. Interior conversion projects tend to cost less, sometimes in the $80,000 to $150,000 range. A precise cost projection can only be developed after a formal feasibility evaluation.

Is ADU construction intrusive while it's underway?

The level of disruption depends on where the ADU is being built. Detached backyard builds are typically less disruptive, since the construction zone is separate. Projects that connect to the main structure may create short-term inconveniences during key milestones. Our team communicates clearly about what to expect at each stage.

Do I need to vacate the property during ADU construction?

Generally speaking, you do not need to vacate your main home during ADU construction. The vast majority of projects are designed so that you remain on the property throughout the build. Certain situations could require a brief departure if interior conversion work touches shared systems in ways that require short-term access disruption. Our project managers will flag these situations during the kickoff meeting.

How long will an ADU built through professional ADU construction hold up?

An ADU constructed with quality materials should last as long as any standard residential structure — indefinitely with proper upkeep. How long it lasts comes down to the quality of materials used, how well routine maintenance is performed, and how proactively issues are resolved over time. Our builds use residential-grade products rated for longevity and build to current California residential standards to protect your investment for the long haul.

ADU Construction for San Jose Homeowners

San Jose's neighborhoods offer a wide range of property types that are well suited for ADU construction. Homeowners in the Willow Glen neighborhood frequently see their parcels are well configured for ADU builds. Neighborhoods near Blossom Hill Road are increasingly popular for ADU construction as families expand. If you're located closer to Evergreen, our team has project experience in the area.

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 the San Jose permitting environment means fewer surprises from design through the final walkthrough.

Schedule Your ADU Construction Consultation Today

When you want to add an ADU to your property, Brother & Brother Builders is ready to guide you. Our builders provide licensed expertise in ADU construction for many different project types — from small attached additions to multi-room backyard residences. Every project starts with a detailed, no-pressure consultation where we learn what you're trying to accomplish and share clear expectations 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're glad to walk through your options, review completed projects and give you the clarity you need to move forward. 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