Unlock New Space with Expert ADU Construction
Homeowners across San Jose, CA are realizing that adding an accessory dwelling unit is one of the smartest investments they can make. ADU construction provides a versatile new living space on your existing property — whether you want to create a private workspace. Brother & Brother Builders has guided hundreds of local homeowners turn these plans to life with precision and integrity.
The popularity of ADU construction has increased significantly in recent years, and it's not hard to see why. California state law has streamlined permitting for homeowners to build these secondary units, and local municipalities like San Jose have embraced 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 functions.
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 planning steps that make an ADU truly livable. Should you want to learn about what ADU construction could mean for your get more info property, this guide will walk you through everything you need to know.
What Is the ADU Construction Process?
ADU construction refers to the process of planning, approving, and constructing 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 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 basement or interior conversions.
Mechanically, everything kicks off with a detailed site assessment, where our team evaluate setbacks, zoning, utility access, and structural feasibility. From there, design plans are prepared and submitted to the relevant municipal authority. Once approvals are in place, ADU construction transitions to the physical build phase — which covers everything from foundational work, framing, HVAC, drywall, flooring, and exterior finishes. The result is a fully functional living unit adjacent to or detached from your main home.
What sets quality ADU construction apart is the depth of planning 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 handles every ADU construction job with the same high standards we bring to full custom home projects.
Key Benefits ADU Construction
- Higher Resale Potential — ADU construction contributes significant market value to your property, often increasing appraised value substantially when it's time to sell.
- Monthly Cash Flow — A completed ADU is leasable as a long-term rental or short-term vacation unit, providing a consistent income stream for the homeowner.
- Space for Loved Ones — ADU construction offers family members a comfortable home of their own without leaving the property.
- Personalized Layouts — From two-bedroom configurations, ADU construction may be customized to your specific needs.
- Streamlined Approval Process — Recent state legislation has reduced the permitting obstacles associated with ADU construction, resulting in a timeline that is faster and more affordable than ever before.
- Efficient Use of Your Lot — Building an ADU uses your existing lot instead of consuming open land, which contributes to sustainability goals.
- Separate Entrances and Spaces — Unlike a bedroom addition, ADU construction produces a fully self-contained unit where tenants live autonomously.
- Durable Return on Investment — A well-built ADU continues to produce returns for the long haul by offering both livable square footage and monetary benefit.
The ADU Construction Process Step by Step
- Property Walkthrough and Feasibility Check — Our team visits your property to analyze zoning rules, slope conditions, and available square footage. This stage clarifies exactly what's possible before any time is invested in drawings.
- Architectural Drafting and Space Planning — Our design team create comprehensive blueprints tailored to your needs. Space is thoughtfully allocated to optimize daily use.
- 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, resolving any revision requests promptly.
- Excavation and Foundation Installation — Once permits are approved, physical construction begins. This includes grading the site, laying the structural base, and establishing utility connections.
- Framing, Roofing, and Exterior Work — Walls and roof systems go up followed by roofing, siding, windows, and exterior doors. This phase, the ADU becomes recognizable as a structure.
- Interior Systems and Infrastructure — Certified technicians install the heating, cooling, drainage, and power infrastructure that make the ADU operationally complete. All work is inspected at designated stages throughout ADU construction.
- Finishes, Fixtures, and Final Walkthrough — Trim, appliances, tile, and lighting are installed and finished to the approved plan. A closing municipal review confirms the unit is code-compliant and your new space is cleared for use.
Who Is a Right Fit for ADU Construction?
Property owners who are best suited from ADU construction often belong to a few common profiles. If you own a single-family home with a backyard, garage, or basement that could be converted, you're already well-positioned. Homeowners hoping to offset mortgage costs through rental are among the most financially driven ADU construction clients, along with families supporting elderly parents.
You may also be someone who needs a dedicated professional workspace and wants a private work environment that remains away from your family's daily life. Property investors and rental owners who already own residential properties are also well suited for ADU construction, since the long-term value is proven.
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. Brother & Brother Builders reviews each property on its own merits to advise you on what's feasible.
ADU Construction FAQ
How long does ADU construction usually take from start to finish?
The full timeline for ADU construction commonly spans six to fourteen months, depending on design complexity and local permitting timelines. The approval phase alone can take a significant portion of the overall timeline in San Jose, so starting early is important. Simpler garage conversions may complete more quickly, while multi-room detached cottages require more time.
What does ADU construction typically cost?
Costs vary widely based on the type and size of the ADU. Locally, ADU construction typically ranges from $150,000 to $400,000 or more for a fully custom construction. Attached ADU additions tend to cost less, sometimes in the $80,000 to $150,000 range. A detailed estimate can only be produced following a thorough property review.
Is ADU construction disruptive while it's underway?
The level of disruption depends on whether you're converting existing space or building new. New construction in the rear yard are usually easier to live alongside, since the crew operates at a distance from your living areas. Projects that connect to the main structure may create short-term inconveniences during certain phases of construction. We provide advance notice about what to expect at each stage.
Do I need to move out during ADU construction?
In most cases, you won't have to vacate your primary residence during ADU construction. Most builds are designed so that you continue living in the home throughout the construction timeline. Certain situations could require a brief departure if interior conversion work touches shared systems in ways that require short-term access disruption. The team at Brother & Brother Builders will discuss these scenarios during the kickoff meeting.
How long will an ADU built through professional ADU construction remain in good condition?
An ADU constructed with quality materials can be expected to last as long as any standard residential structure — typically 50 years or more. Longevity is tied to the quality of materials used, how consistently minor repairs are addressed, and if mechanical components are maintained on schedule. Our builds use 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
Residential areas across San Jose present a variety of property types that are well suited for ADU construction. Homeowners in the Willow Glen neighborhood frequently see their parcels accommodate detached backyard units nicely. The Berryessa area are increasingly popular for ADU construction as housing demand rises. If you're located closer to Evergreen, our team has project experience in the area.
Local regulatory bodies in this area applies particular standards for ADU construction that require a builder familiar with local expectations. Location near major arterials like Story Road or Tully Road 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 the team to call. Our experts offer licensed expertise in ADU construction across a wide range of project types — from modest studio builds to fully independent secondary homes. The process begins with a comprehensive site assessment where we learn what you're trying to accomplish and share clear expectations of what's achievable.
Get in touch with our office to schedule a site visit. Even if you're just exploring the idea, we're glad to discuss timelines, costs, and design possibilities and help you take the next step. 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