Brother & Brother Builders

Transform Your Property with Expert ADU Construction

Property owners throughout San Jose, CA are realizing that adding an accessory dwelling unit is one of the smartest investments they can make. ADU construction creates a powerful new living space on your existing property — whether you want to house a family member. Brother & Brother Builders has guided hundreds of local homeowners bring these projects to life with craftsmanship and care.

The popularity of ADU construction has grown rapidly in recent years, and it's not hard to see why. California state law now makes it easier for homeowners to add these secondary units, and local municipalities like San Jose have supported the trend as a way to increase density responsibly. Whether you're building 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 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 truly livable. Should you want to learn about what ADU construction could mean for your property, this guide covers everything you need to know.

What Is the ADU Construction Process?

ADU construction involves the process of planning, approving, and constructing an accessory dwelling unit on a residential property. An accessory dwelling unit is a complete living space — including a kitchen, bathroom, sleeping area, and its own access point — that is located on the same parcel as a primary residence. ADU construction includes various structural types, including detached backyard units, attached additions, garage conversions, and even basement or interior conversions.

Mechanically, the work starts with a thorough property evaluation, where our team evaluate lot dimensions, existing structures, soil conditions, and local code requirements. From there, architectural drawings are prepared and submitted to the city for permit approval. Once the paperwork is cleared, ADU construction enters the physical build phase — which encompasses site preparation, framing, roofing, plumbing, electrical, insulation. The result is a completely finished living unit attached to or separate from your main home.

What sets quality ADU construction apart is the attention to detail at every stage. Components should be specified to align with the neighborhood's character. Systems like HVAC and drainage must be designed to handle full-time occupancy. Brother & Brother Builders treats each project with the same high standards we bring to full custom home projects.

Key Benefits 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.
• Revenue Generation — A completed ADU may be listed as a long-term rental or short-term vacation unit, creating ongoing passive income for the homeowner.
• Space for Loved Ones — ADU construction offers family members a self-contained residence without losing proximity to the family.
• Customization Options — From two-bedroom configurations, ADU construction is adaptable to the intended occupant's lifestyle.
• Faster Permitting in California — Recent state legislation has reduced the red tape associated with ADU construction, making the process that is faster and less expensive than ever before.
• Efficient Use of Your Lot — Building an ADU maximizes the land you already own instead of consuming open land, which supports broader sustainability goals.
• Separate Entrances and Spaces — Unlike a bedroom addition, ADU construction produces a fully self-contained unit where tenants live autonomously.
• 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 Journey Step by Step

1. Site Evaluation and Zoning Analysis — Our builders assess your property to analyze zoning rules, slope conditions, and available square footage. This step tells you exactly what can be built before any time is invested in drawings.
2. Architectural Drafting and Space Planning — Experienced draftspeople create comprehensive blueprints based on your goals. Every square foot is planned 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 review and approval. Our team handles all submissions on your behalf, responding to review feedback promptly.
4. Excavation and Foundation Installation — Once permits are granted, on-site work kicks off. This involves leveling and prepping the ground, laying the structural base, and running initial plumbing and electrical conduits.
5. Framing, Roofing, and Exterior Work — The structural frame is erected followed by weatherproofing and exterior finish materials. This phase, the ADU becomes recognizable as a structure.
6. Interior Systems and Infrastructure — Skilled tradespeople install the plumbing lines, electrical wiring, and HVAC systems that make the ADU fully functional. Every system is reviewed at required milestones throughout ADU construction.
7. Interior Finishing and Final Inspections — Countertops, hardware, finishes, and fixtures are fitted and completed to the agreed design. A final city inspection issues the certificate of occupancy 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 common profiles. If you are a homeowner with a backyard, garage, or basement that could be converted, you're already in a good starting place. Homeowners looking to generate income through rental are among the most financially driven ADU construction clients, along with families supporting elderly parents.

ADU construction also suits someone who works from home and wants a private work environment that remains away from your family's daily life. Property investors and rental owners who are building a portfolio are also a natural fit for ADU construction, since the long-term value is proven.

Situations where ADU construction may not be the best first step include properties with significant setback limitations. Parcels in historic districts or HOA-restricted communities may need a modified approach. Our team can assess 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 complete duration for ADU construction typically ranges from six to fourteen months, influenced by the type of unit being built and city review schedules. The approval phase alone can take several months in San Jose, so planning ahead matters. Smaller detached units often finish in the lower end of the range, while custom detached builds take longer to complete.

What does ADU construction typically cost?

Pricing depends on many factors based on the type and size of the ADU. For most projects in this region, ADU construction generally falls between $150,000 to $400,000 or more for a standalone backyard unit. Interior conversion projects tend to cost less, sometimes starting around $80,000 depending on scope. A detailed estimate can only be developed after 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. New construction in the rear yard are generally the least intrusive, since work happens away from the main house. 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 move out during ADU construction?

For more info the majority of homeowners, you won't have to vacate your primary residence during ADU construction. The vast majority of projects are structured to allow you stay in your primary unit throughout the process. There are edge cases if major utility upgrades affect the main house in ways that briefly affect habitability. The team at Brother & Brother Builders will discuss these scenarios during the kickoff meeting.

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

Any ADU built to code with professional oversight is designed to last as long as the main residence — often several decades with routine maintenance. Durability depends to the standard of construction, whether the unit is properly cared for, and whether systems like roofing and plumbing are serviced regularly. We select residential-grade products rated for longevity and build to current California residential standards to ensure lasting performance.

ADU Construction for Local Homeowners

The communities throughout San Jose provide a variety of property types that are ideally positioned for ADU construction. Residents in the Rose Garden district have found their lots are well configured for ADU builds. The Berryessa area are seeing more homeowners add secondary units as multigenerational living becomes more common. From neighborhoods near the Guadalupe River Park corridor to those near Branham Lane, our team knows the permitting landscape well.

San Jose's permitting office follows defined procedures 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. Our team's knowledge of the San Jose permitting environment means fewer surprises from kickoff through certificate of occupancy.

Schedule Your ADU Construction Consultation Today

Should you be thinking about how to move forward with ADU construction, Brother & Brother Builders is here to help. Our builders provide proven skills in ADU construction including all types of project types — from modest studio builds to multi-room backyard residences. Every project starts with a thorough and honest property review where we understand your vision and provide an honest assessment of what the project will involve.

Contact Brother & Brother Builders to schedule a site visit. Whether you're in the early stages of planning, we're glad to walk through your options, review completed projects and help you take the next step. 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