Brentwood is one of the Bay Area’s most desirable family-friendly communities, offering space, comfort, and strong long-term property value. For homeowners here, building an Accessory Dwelling Unit (ADU) is the perfect way to adapt to changing needs—whether you want to house family, generate passive income, or expand your living space for work or relaxation.

At Royalty Builders, we provide full-service ADU design and construction tailored to Brentwood’s zoning, architecture, and lifestyle. From planning and permits to finished construction, we handle everything—so you can focus on the possibilities.

Types of ADUs We Build in Brentwood

With generous lot sizes and diverse home styles, Brentwood is ideal for a wide variety of ADU options. At Royalty Builders, we design ADUs that match your goals, your budget, and your home’s style.

We build:

• Detached ADUs – Ideal for guesthouses, long-term rentals, or multigenerational living

• Attached ADUs – Seamless expansions that blend with your existing home

• Garage Conversions – Efficient and cost-effective way to add livable square footage

• Above-Garage ADUs – A smart option for adding space vertically

• Basement Conversions – Great for creating fully equipped lower-level suites

Every unit is fully customized to meet Brentwood’s building code and your personal style.

Full-Service ADU Design + Build in Brentwood

We make the process simple and seamless with our design-build model. With Royalty Builders, you get one expert team that manages everything—from architecture and engineering to permitting and construction.

Our complete service includes:

• Property analysis and zoning feasibility

• Custom architectural and structural design

• Title 24 energy documentation and engineering

• Full permitting with the City of Brentwood

• Professional construction and project management

• Final inspection, occupancy approval, and utility setup

With Royalty Builders, your ADU will be delivered on time, on budget, and built to last.

How Much Does It Cost to Build an ADU in Brentwood?

Brentwood’s competitive real estate market and family-friendly lifestyle make ADU construction a high-value investment. Costs vary depending on the unit type, finishes, and existing lot conditions, and we provide full transparency from day one.

Typical ADU pricing in Brentwood:

• Garage Conversion: $110,000 – $160,000

• Attached ADU: $170,000 – $270,000

• Detached ADU: $200,000 – $340,000+

• Above-Garage ADU: $220,000 – $360,000

We also help you explore financing options, such as home equity loans or renovation-specific funding, to make your project easier to manage.

Permits for ADU Construction in Brentwood – What You Need to Know

Brentwood complies with California’s ADU regulations, but local ordinances still apply. Royalty Builders has experience working directly with the City of Brentwood’s Building and Planning departments, so we know how to keep your project compliant and on schedule.

We take care of:

• Reviewing zoning, setbacks, and height restrictions

• Submitting architectural and structural plans

• Managing corrections and plan revisions

• Scheduling inspections and coordinating with city officials

• Ensuring code compliance and final approvals

Let us handle the paperwork while you plan your new space.

Why Build an ADU in Brentwood?

Brentwood offers large lots, great schools, and strong resale value—making it one of the best places in Contra Costa County to invest in an ADU. Whether you’re looking to support your family or future-proof your home, now is the time to build.

Top reasons Brentwood homeowners build ADUs:

• 🏡 Create private living space for family, guests, or caregivers

• 💼 Set up a home office or creative studio away from distractions

• 💰 Generate rental income in a growing local housing market

• 📈 Increase your home’s value with desirable living space

• 🔄 Plan for aging in place or future resale flexibility

A well-designed ADU enhances your lifestyle—and your financial future.

Frequently Asked Questions – ADUs in Brentwood

Q: How large can an ADU be in Brentwood?
A: Detached ADUs can typically be up to 1,200 sq. ft., depending on your lot and setbacks. We’ll help determine what’s possible on your property.

Q: Do I need to add parking for an ADU?
A: In many cases, no. Garage conversions and ADUs near transit may be exempt from parking requirements. We’ll confirm during your consultation.

Q: Can I rent out my ADU in Brentwood?
A: Yes, long-term rentals are permitted for ADUs. We’ll ensure your unit meets all legal requirements for occupancy.

Q: What’s the timeline for building an ADU?
A: Most ADUs take 6–10 months from planning to completion. We provide a clear project timeline upfront and keep you updated at every step.

Contact Royalty Builders – Brentwood’s ADU Experts

Ready to expand your Brentwood home with a smart, stylish ADU? Let Royalty Builders help you design and build a beautiful space that adds value, function, and flexibility to your life.

📞 Contact us today and schedule your free ADU consultation in Brentwood.

Premium service. Practical space. Built with Royalty.