Transform Your Property 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 provides a flexible new living space on your existing property — whether you want to create a private workspace. Brother & Brother Builders has supported hundreds of local homeowners bring these projects to life with craftsmanship and transparency.
The demand for ADU construction has grown rapidly in recent years, and it's easy to understand why. California state law has simplified the process for homeowners to build these secondary units, and local municipalities like San Jose have encouraged the trend as a way to increase density responsibly. Whether you want to build a detached backyard cottage, a garage conversion, or an attached addition, ADU construction offers greater control over how your property serves your household.
At Brother & Brother Builders, we bring years of hands-on experience to every ADU construction job. Our team knows adu construction near San Jose the San Jose building codes, the engineering details, and the aesthetic decisions that make an ADU functional. Should you want to learn about what ADU construction could mean for your property, this guide explains everything you need to know.
What Is the ADU Construction Process?
ADU construction describes 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 entryway — that sits on the same property as a primary residence. ADU construction comes in multiple configurations, including detached backyard units, attached additions, garage conversions, and even basement or interior conversions.
Mechanically, the process begins 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 local building department. Once permits are secured, ADU construction enters the physical build phase — which includes foundation work, framing, roofing, plumbing, electrical, insulation. The result is a move-in-ready living unit attached to or separate from your main home.
The difference between a good and a great ADU build is the level of craftsmanship at every stage. Materials must be selected to align with the neighborhood's character. Systems like plumbing and electrical must be designed to handle full-time occupancy. Brother & Brother Builders handles every ADU construction job with the same high standards we apply to large-scale custom home projects.
Key Reasons to Choose ADU Construction
- Boosted Home Equity — 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 may be listed as a long-term rental or short-term vacation unit, providing a consistent income stream for the homeowner.
- Space for Loved Ones — ADU construction gives aging parents a comfortable home of their own without moving to another neighborhood.
- Design Flexibility — From open-plan one-bedrooms, 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, creating a path that is faster and more affordable than ever before.
- Responsible Property Development — Building an ADU works within your current footprint instead of requiring new development, which aligns with sustainability goals.
- Privacy for All Residents — Unlike a bedroom addition, ADU construction creates a truly separate unit where occupants have full privacy.
- Long-Term Investment Security — A well-built ADU continues to produce returns for many years and generates both functional space and financial upside.
The ADU Construction Journey Step by Step
- Property Walkthrough and Feasibility Check — Our experts review your property to evaluate setbacks, lot coverage limits, and utility connections. This stage clarifies exactly what can be built before any time is invested in drawings.
- Custom Design and Architectural Planning — Experienced draftspeople create detailed floor plans based on your goals. Every square foot is planned 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. Brother & Brother Builders coordinates the permitting on your behalf, addressing any city comments promptly.
- Site Preparation and Foundation Work — Once permits are approved, the build starts. This covers land preparation, laying the structural base, and establishing utility connections.
- Shell Construction and Exterior Finishing — The structural frame is erected followed by weatherproofing and exterior finish materials. At this stage, the ADU takes its visible shape.
- Mechanical, Electrical, and Plumbing Installation — Skilled tradespeople install the heating, cooling, drainage, and power infrastructure that make the ADU fully functional. Every system is reviewed at each code checkpoint throughout ADU construction.
- Interior Completion and City Sign-Off — Flooring, cabinetry, fixtures, paint are fitted and completed to the approved plan. A closing municipal review confirms the unit is code-compliant and the ADU is ready for use.
Who Is a Right Fit for ADU Construction?
Property owners who are best suited from ADU construction often belong to a few recognizable groups. If you are a homeowner with a backyard, garage, or basement that could be converted, you're already a strong candidate. Homeowners looking to generate income 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 needs a dedicated professional workspace and wants a private work environment that doesn't interfere with your family's daily life. Landlords and real estate investors who already own residential properties are also prime candidates for ADU construction, since the return on investment is well-documented.
Homeowners who may want to pause and evaluate 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 recommend the right path forward.
ADU Construction FAQ
How long does ADU construction usually take from start to finish?
The full timeline for ADU construction typically ranges from six to fourteen months, influenced by the type of unit being built and how quickly approvals come through. City review on its own can take several months in San Jose, so beginning the process sooner rather than later is wise. Smaller detached units can move faster, while custom detached builds require more time.
What does ADU construction usually run in terms of budget?
Costs vary widely 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 fully custom construction. Garage conversions are generally priced lower, sometimes in the $80,000 to $150,000 range. A detailed estimate can only be developed after a thorough property review.
Is ADU construction disruptive while it's underway?
The level of disruption depends on where the ADU is being built. Standalone ADU projects are typically less disruptive, since work happens away from the main house. Interior conversions may create short-term inconveniences during specific stages like framing or MEP rough-in. Brother & Brother Builders keeps you informed about upcoming work and timelines.
Do I need to move out during ADU construction?
Generally speaking, you do not need to vacate your house during ADU construction. Most job sites are set up to let you continue living in the home throughout the process. Exceptions may arise if interior conversion work touches shared systems in ways that temporarily impact livability. Our construction supervisors will flag these situations during the pre-construction consultation.
How long will an ADU built through professional ADU construction hold up?
Any ADU built to code with professional oversight should last as long as your primary home — indefinitely with proper upkeep. Longevity is tied to the standard of construction, whether the unit is properly cared for, and how proactively issues are resolved over time. Brother & Brother Builders specifies high-quality components and follow all code requirements to deliver a structure that stands the test of time.
ADU Construction for San Jose Homeowners
Residential areas across San Jose present a diverse mix 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 multigenerational living becomes more common. If you're located closer to Evergreen, our team has project experience in the area.
San Jose's permitting office 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 the San Jose permitting environment means more accurate timelines and budgets from kickoff through certificate of occupancy.
Schedule Your ADU Construction Assessment Today
If you're ready 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 for many different project types — from small attached additions to fully independent secondary homes. Every project starts with a thorough and honest property review where we learn what you're trying to accomplish and share clear expectations of what ADU construction on your property will look like.
Contact Brother & Brother Builders to set up your consultation. Even if you're just exploring the idea, we enjoy answer questions, share examples of our work and give you the clarity you need to move forward. ADU construction is a significant investment — and we're committed to helping you get it right.
Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632