Brother & Brother Builders

Expand Your Home with Quality ADU Construction

Families in San Jose, CA are finding that adding an accessory dwelling unit is one of the most practical investments they can make. ADU construction creates a powerful new living space on your existing property — whether you want to create a private workspace. Brother & Brother more info Builders has guided hundreds of local homeowners bring these projects to life with skill and transparency.

The demand for ADU construction has increased significantly in recent years, and it's not hard to see 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 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 serves your household.

At Brother & Brother Builders, we draw on extensive hands-on experience to every ADU construction project. Our team understands the local permitting process, the engineering requirements, and the aesthetic decisions that make an ADU beautiful. When you're ready to explore what ADU construction could do for your property, this guide explains everything you need to know.

What Is an ADU Build?

ADU construction involves the process of designing, permitting, and building an accessory dwelling unit on a residential property. An accessory dwelling unit is a complete living space — featuring a kitchen, bathroom, sleeping area, and its own entrance — 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 basement or interior conversions.

Mechanically, the work starts with a comprehensive review of your lot, where our team evaluate property boundaries, available square footage, and infrastructure capacity. From there, design plans are prepared and submitted to the relevant municipal authority. Once approvals are in place, ADU construction moves into the physical build phase — which includes foundation work, framing, roofing, plumbing, electrical, insulation. The result is a move-in-ready living unit adjacent to or detached from your main home.

What separates excellent ADU construction from an average project is the depth of planning at every stage. Products need to be chosen to match the primary home's aesthetic. Systems like HVAC and drainage must be designed to handle full-time occupancy. Brother & Brother Builders treats each project with the same professional rigor we bring to full custom home projects.

Key Advantages ADU Construction

• Higher Resale Potential — ADU construction delivers real 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, generating steady monthly revenue for the homeowner.
• Multi-Generational Living — ADU construction provides adult children a self-contained residence without moving to another neighborhood.
• Customization Options — From two-bedroom configurations, ADU construction is adaptable to your household's priorities.
• Faster Permitting in California — Recent state legislation has cut down 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 maximizes the land you already own instead of expanding urban sprawl, which contributes to sustainability goals.
• Separate Entrances and Spaces — Unlike a bedroom addition, ADU construction creates a truly separate unit where tenants live autonomously.
• Lasting Financial Benefit — A well-built ADU holds its value for many years and generates both functional space and financial upside.

The ADU Construction Procedure Step by Step

1. Property Walkthrough and Feasibility Check — 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 resources go toward planning.
2. Blueprint Development and Layout Design — Licensed architects and designers create detailed floor plans based on your goals. Every square foot is planned to maximize function and livability.
3. Filing for Building Permits — ADU construction in San Jose demands documentation to the city's building department for sign-off and verification. We manage this entire process on your behalf, addressing any city comments promptly.
4. Excavation and Foundation Installation — Once permits are issued, on-site work kicks off. This involves leveling and prepping the ground, pouring the concrete foundation, and establishing utility connections.
5. Shell Construction and Exterior Finishing — Framing is completed followed by roofing, siding, windows, and exterior doors. This phase, the ADU transforms from a concept to a building.
6. Mechanical, Electrical, and Plumbing Installation — Certified technicians install the heating, cooling, drainage, and power infrastructure that make the ADU ready for occupancy. Every system is reviewed at each code checkpoint throughout ADU construction.
7. Interior Finishing and Final Inspections — Trim, appliances, tile, and lighting are fitted and completed to the agreed design. A final city inspection issues the certificate of occupancy and the ADU is ready 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 have a residential property 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 navigating multigenerational living situations.

ADU construction also suits someone who works from home and wants a detached creative or business space that remains away from your family's daily life. Real estate-minded homeowners who are building a portfolio are also prime candidates for ADU construction, since the return on investment is well-documented.

Those who should discuss alternatives first include properties with significant setback limitations. Very small lots or properties with easements may face additional constraints. 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 generally take from start to finish?

The total process for ADU construction usually runs between six to fourteen months, based on the project scope and city review schedules. Permitting alone 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 typically cost?

Pricing depends on many factors based on the type and size of the ADU. In the San Jose area, ADU construction commonly costs $150,000 to $400,000 or more for a fully custom construction. Interior conversion projects tend to cost less, sometimes starting around $80,000 depending on scope. An accurate budget can only be developed after a formal feasibility evaluation.

Is ADU construction disruptive while it's underway?

The level of disruption depends on the project's location on your property. New construction in the rear yard are generally the least intrusive, since the construction zone is separate. Projects that connect to the main structure may require temporary access during specific stages like framing or MEP rough-in. Our team communicates clearly about upcoming work and timelines.

Do I need to vacate the property during ADU construction?

Generally speaking, you do not need to vacate your house during ADU construction. Most job sites are designed so that you continue living in the home throughout the build. Certain situations could require a brief departure if significant structural connections require temporary shutoffs in ways that briefly affect habitability. Our construction supervisors will discuss these scenarios during the pre-construction consultation.

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

A well-built ADU can be expected to last as long as the main residence — indefinitely with proper upkeep. How long it lasts comes down to the standard of construction, how well routine maintenance is performed, and how proactively issues are resolved over time. Brother & Brother Builders specifies high-quality components and build to current California residential standards to deliver a structure that stands the test of time.

ADU Construction for San Jose Homeowners

The communities throughout San Jose provide a variety of property types that are perfectly suited for ADU construction. Residents in the Rose Garden district frequently see their parcels work well for both attached and detached projects. Communities around the Capitol Expressway corridor have seen growing ADU activity as families expand. Whether your property is near downtown San Jose, our team has likely worked nearby.

The City of San Jose's building department has developed specific protocols for ADU construction that require a builder familiar with local expectations. Proximity to transit corridors can affect how quickly permits are approved for a given ADU project. Brother & Brother Builders' experience across this region's building landscape means fewer surprises from design through the final walkthrough.

Book Your ADU Construction Assessment Today

When you want to add an ADU to your property, Brother & Brother Builders is the team to call. We bring licensed expertise in ADU construction for many different project types — from modest studio builds to large custom detached cottages. The process begins with a detailed, no-pressure consultation where we listen to your goals and give you a realistic picture of what ADU construction on your property will look like.

Contact Brother & Brother Builders to begin the conversation. No matter where you are in the decision-making process, our team is happy to walk through your options, review completed projects and make sure you feel confident before committing. This type of project is a meaningful commitment — and we want to make sure it's the right one for you.

Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632