Brother & Brother Builders

Transform Your Property with Professional ADU Construction

Property owners throughout San Jose, CA are discovering that adding an accessory dwelling unit is one of the most practical investments they can make. ADU construction opens the door to a versatile new living space on your existing property — whether you want to generate rental income. Brother & Brother Builders has guided hundreds of local homeowners see these visions to life with skill and care.

The demand for ADU construction has increased significantly in recent years, and it's not hard to see why. California state law has simplified the process for homeowners to build these secondary units, and local municipalities like San Jose have supported the trend as a way to address housing needs. 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 works.

At Brother & Brother Builders, we apply deep hands-on experience to every ADU construction job. Our team understands the local permitting process, the engineering considerations, and the design choices that make an ADU beautiful. Should you want to learn about what ADU construction could do for your property, this guide will walk you through everything you need to know.

What Is ADU Construction?

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 — featuring a kitchen, bathroom, sleeping area, and its own entrance — that is located on the same parcel 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, everything kicks off with a detailed site assessment, where our team evaluate lot dimensions, existing structures, soil conditions, and local code requirements. From there, design plans are prepared and submitted to the local building department. Once the paperwork is cleared, 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 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. Components should be specified to match the primary home's aesthetic. Systems like plumbing and electrical must be designed to handle full-time occupancy. Brother & Brother Builders approaches every build with the same professional rigor we bring to full custom home projects.

Key Benefits ADU Construction

• Increased Property Value — ADU construction adds measurable 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, providing a consistent income stream for the homeowner.
• Space for Loved Ones — ADU construction provides adult children a self-contained residence without losing proximity to the family.
• Customization Options — From open-plan one-bedrooms, ADU construction can be tailored to your household's priorities.
• Faster Permitting in California — Recent state legislation has minimized the red tape associated with ADU construction, making the process that is faster and more affordable than ever before.
• Responsible Property Development — Building an ADU uses your existing lot instead of consuming open land, which contributes to sustainability goals.
• Independent Living Areas — 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 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 stage clarifies exactly what's possible before any time is invested in drawings.
2. Blueprint Development and Layout Design — Our design team create comprehensive blueprints reflecting your priorities. Layouts are carefully considered to optimize daily use.
3. Permitting and City Approval — ADU construction in San Jose demands documentation to the city's building department for inspection and clearance. Brother & Brother Builders coordinates the permitting on your behalf, resolving any revision requests promptly.
4. Site Preparation and Foundation Work — Once permits are granted, the build starts. This covers land preparation, pouring the concrete foundation, and setting up utilities.
5. Framing, Roofing, and Exterior Work — The structural frame is erected followed by weatherproofing and exterior finish materials. This phase, the ADU transforms from a concept to a building.
6. MEP Systems Rough-In — Skilled tradespeople install the heating, cooling, drainage, and power infrastructure that make the ADU operationally complete. Inspections are completed at each code checkpoint throughout ADU construction.
7. Interior Finishing and Final Inspections — Trim, appliances, tile, and lighting are fitted and completed to your specifications. A closing municipal review issues the certificate of occupancy and the ADU is ready for use.

Who Is a Good Candidate for ADU Construction?

People who see the greatest return from ADU construction often belong to a few common profiles. 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 motivated ADU construction clients, along with families supporting elderly parents.

You may also be someone who runs a small business and wants a separate office or studio space that doesn't interfere with your family's daily life. Real estate-minded homeowners who already own residential properties are also a natural fit for ADU construction, since the return on investment is well-documented.

Those who should discuss alternatives first include lots that are below minimum size thresholds. Very small lots or properties with easements may face additional constraints. Our experts will evaluate each property individually and honestly to advise you on what's feasible.

ADU Construction Frequently Asked Questions

How long does ADU construction usually take from start to finish?

The total process for ADU construction commonly spans six to fourteen months, influenced by the type of unit being built and local permitting timelines. City review on its own can take several months in San Jose, so starting early is important. Straightforward interior conversions can move faster, while larger new construction ADUs fall toward the upper end of the timeline.

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 typically ranges from $150,000 to $400,000 or more for a detached new build. Garage read more conversions often come in under, sometimes in the $80,000 to $150,000 range. An accurate budget can only be developed after a full site assessment.

Is ADU construction intrusive while it's underway?

The level of disruption depends on where the ADU is being built. Standalone ADU projects are generally the least intrusive, since the construction zone is separate. Interior conversions may create short-term inconveniences during key milestones. 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 primary residence during ADU construction. Most job sites are structured to allow you remain on the property throughout the build. Certain situations could require a brief departure if major utility upgrades affect the main house 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 remain in good condition?

A well-built ADU is designed to last as long as your primary home — typically 50 years or more. How long it lasts comes down to the systems installed, whether the unit is properly cared for, and if mechanical components are maintained on schedule. We select commercial-grade materials and follow all code requirements to protect your investment for the long haul.

ADU Construction for San Jose Homeowners

The communities throughout San Jose provide a wide range of property types that are well suited for ADU construction. Property owners near the Almaden Valley area have found their lots are well configured for ADU builds. The Berryessa area have seen growing ADU activity as housing demand rises. Whether your property is near downtown San Jose, our team has project experience in the area.

Local regulatory bodies in this area applies particular standards for ADU construction that experienced builders know well. Access to infrastructure along thoroughfares like Monterey Road can impact the design approach for a given ADU project. Our familiarity with this region's building landscape means fewer surprises from the first meeting to the final inspection.

Start Your ADU Construction Consultation Today

When you want to explore what an ADU could look like on your lot, Brother & Brother Builders is ready to guide you. Our builders provide licensed expertise in ADU construction for many different project types — from modest studio builds to large custom detached cottages. The process begins with a thorough and honest property review where we learn what you're trying to accomplish and give you a realistic picture of what's achievable.

Reach out to our team to schedule a site visit. No matter where you are in the decision-making process, we enjoy discuss timelines, costs, and design possibilities and help you take the next step. 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