Transform Your Property with Quality ADU Construction
Property owners throughout San Jose, CA are discovering that adding an accessory dwelling unit is one of the smartest investments they can make. ADU construction provides a flexible new living space on your existing property — whether you want to generate rental income. Brother & Brother Builders has helped hundreds of local homeowners turn these plans to life with craftsmanship and integrity.
The popularity of ADU construction has surged in recent years, and it's no mystery. California state law has simplified the process for homeowners to construct these secondary units, and local municipalities like San Jose have embraced 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 offers greater control over how your property works.
At Brother & Brother Builders, we bring years of hands-on experience to every ADU construction job. Our team is familiar with city and county requirements, the engineering requirements, and the design choices that make an ADU truly livable. Should you want to learn about what ADU construction could look like on 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 unit on a residential property. An accessory dwelling unit is a complete living space — including a kitchen, bathroom, sleeping area, and its own entrance — that sits on the same property 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 process begins with a thorough property evaluation, where our builders evaluate lot dimensions, existing structures, soil conditions, and local code requirements. From there, blueprints are prepared and submitted to the local building department. Once the paperwork is cleared, ADU construction moves into the physical build phase — which includes foundation work, framing, roofing, plumbing, electrical, insulation. The result is a completely finished living unit attached to or separate from your main home.
The difference between a good and a great ADU build is the attention to detail at every stage. Materials must be selected 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 use on major 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.
- Monthly Cash Flow — A completed ADU can be rented as a long-term rental or short-term vacation unit, providing a consistent income stream for the homeowner.
- Multi-Generational Living — ADU construction gives aging parents a comfortable home of their own without leaving the property.
- Customization Options — From modern studio layouts, ADU construction is adaptable to your household's priorities.
- Simplified Regulatory Path — Recent state legislation has minimized the permitting obstacles associated with ADU construction, making the process that is faster and more affordable than ever before.
- Responsible Property Development — Building an ADU works within your current footprint instead of expanding urban sprawl, which supports broader sustainability goals.
- Independent Living Areas — Unlike a bedroom addition, ADU construction delivers a genuinely independent unit where tenants live autonomously.
- Durable Return on Investment — A well-built ADU remains an asset for the long haul by offering both livable square footage and monetary benefit.
The ADU Construction Process Step by Step
- Site Evaluation and Zoning Analysis — Our team visits your property to evaluate setbacks, lot coverage limits, and utility connections. This step tells you exactly what ADU types will work before any money is spent on design.
- Architectural Drafting and Space Planning — Licensed architects and designers create precise architectural drawings reflecting your priorities. Space is thoughtfully allocated to maximize function and livability.
- Permit Submission and Municipal Review — 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, resolving any revision requests promptly.
- Site Preparation and Foundation Work — Once permits are issued, physical construction begins. This includes grading the site, pouring the concrete foundation, and setting up utilities.
- Structural Framing and Weatherproofing — Walls and roof systems go up followed by weatherproofing and exterior finish materials. During this step, the ADU becomes recognizable as a structure.
- Mechanical, Electrical, and Plumbing Installation — Licensed subcontractors install the heating, cooling, drainage, and power infrastructure that make the ADU ready for occupancy. Inspections are completed at designated stages throughout ADU construction.
- Interior Finishing and Final Inspections — Countertops, hardware, finishes, and fixtures are installed and finished to your specifications. A closing municipal review grants legal occupancy status 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 enough lot space to meet setback requirements, you're already well-positioned. Homeowners looking to generate income through rental are among the most common ADU construction clients, along with families navigating multigenerational living situations.
ADU construction also suits someone who runs a small business and wants a separate office or studio space that remains away from your family's daily life. Property investors and rental owners who want to maximize their land are also well suited for ADU construction, since the return on investment is well-documented.
Situations where ADU construction may not be the best first step include sites with unusual utility access challenges. Very small lots or properties with easements may face additional constraints. Our experts will evaluate each property individually and honestly to provide realistic options.
ADU Construction FAQ
How long does ADU construction typically take from start to finish?
The full timeline for ADU construction commonly spans six to fourteen months, influenced by the type of unit being built and city review schedules. City review on its own can take several months in San Jose, so starting early is important. Straightforward interior conversions often finish in the lower end of the range, while multi-room detached cottages 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 typically ranges from $150,000 to $400,000 or more for a standalone backyard unit. Garage conversions often come in under, sometimes between $75,000 and $140,000. A detailed estimate can only be produced following a full site assessment.
Is ADU construction disruptive while it's underway?
The level of disruption depends on where the ADU is being built. Detached backyard builds are usually easier to live alongside, since work happens away from the main house. Garage conversions or attached additions may create short-term inconveniences during certain phases of construction. We provide advance notice about any phases that may affect your routine.
Do I need to leave my home during ADU construction?
Generally speaking, you are not required to vacate your house during ADU construction. Most builds are set up to let you remain on the property throughout the build. Certain situations could require a brief departure if significant structural connections require temporary shutoffs in ways that briefly affect habitability. Our project managers will discuss these scenarios during the pre-construction consultation.
How long will an ADU built through professional ADU construction remain in good condition?
A well-built ADU should last as long as your primary home — typically 50 years or more. Durability depends to the quality of materials used, how well routine maintenance is performed, and if mechanical components are maintained on schedule. Our builds use commercial-grade materials and follow all code requirements to deliver a structure that stands the test of time.
ADU Construction for Local Homeowners
Residential areas across San Jose present a wide range of property types that are ideally positioned for ADU construction. Residents in the Rose Garden website district often discover their properties are well configured for ADU builds. Communities around the Capitol Expressway corridor are seeing more homeowners add secondary units as housing demand rises. Whether your property is near downtown San Jose, our team knows the permitting landscape well.
Local regulatory bodies in this area has developed specific protocols for ADU construction that our team navigates routinely. 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 design through the final walkthrough.
Start Your ADU Construction Assessment Today
When you want to move forward with ADU construction, Brother & Brother Builders is the team to call. Our builders provide years of hands-on experience in ADU construction across a wide range of project types — from modest studio builds to fully independent secondary homes. The process begins with a detailed, no-pressure consultation where we understand your vision and provide an honest assessment of what's achievable.
Contact Brother & Brother Builders to set up your consultation. Whether you're in the early stages of planning, we enjoy discuss timelines, costs, and design possibilities and give you the clarity you need to move forward. Building an ADU is a major decision — and we're committed to helping you get it right.
Brother & Brother Builders | 3109 Stevens Creek Boulevard | San Jose CA 95117 | (888) 412-2632