In a city like San Mateo—where property is valuable and space is at a premium—building an ADU (Accessory Dwelling Unit) is one of the smartest ways to enhance your home’s usability, value, and potential income. Whether you need more room for extended family, a home office, or a rental unit to generate passive income, Royalty Builders specializes in making your ADU vision a reality—efficiently, elegantly, and with full transparency.

With demand for housing continuing to rise throughout the Bay Area, San Mateo homeowners are discovering that a well-planned ADU isn’t just an addition—it’s a transformation.

Types of ADUs We Build in San Mateo

Every homeowner and property is different, which is why Royalty Builders offers a variety of ADU solutions tailored to your goals, budget, and lot size. From compact in-law units to expansive backyard homes, we bring creativity, structural know-how, and compliance expertise to every build.

Here are the primary types of ADUs we construct in San Mateo:

• Detached ADUs – Freestanding units perfect for rental income, guest suites, or family housing. Offers maximum privacy.

• Attached ADUs – Built as an extension of your existing home, often sharing one wall. Great for multigenerational living.

• Garage Conversions – Turn your underused garage into a beautiful, fully functional living space. Cost-effective and fast.

• Above-Garage Units – Take advantage of vertical space with a stylish loft or studio over your existing garage.

• Basement ADUs – If your home has a basement, converting it into a legal unit can unlock serious value.

We help you choose the most efficient layout for your lot and lifestyle, while maximizing return on investment.

Full-Service ADU Design + Build in San Mateo

Royalty Builders offers a complete design-build solution for San Mateo ADU projects. This means you’ll work with one experienced team from concept to completion—eliminating the headache of juggling architects, engineers, city offices, and contractors.

Our process includes:

• On-site evaluation & zoning analysis

• Architectural design tailored to your vision

• Engineering and structural planning

• Full permit handling

• Construction, finishing, and inspections

• Seamless utility hookups and final walkthrough

Our experienced team will guide you through each phase with full transparency, frequent updates, and solutions to any unexpected issues along the way.

How Much Does It Cost to Build an ADU in San Mateo?

Building an ADU in San Mateo is a serious investment—but one that often pays for itself in rental income and increased property value. The cost depends on several factors, including the size of the ADU, your design preferences, site conditions, and whether you’re starting from scratch or converting existing space.

Typical San Mateo ADU pricing:

• Garage conversions: $120,000 – $180,000

• Attached or above-garage ADUs: $180,000 – $300,000

• Detached new builds: $200,000 – $350,000+

We offer detailed cost breakdowns and custom quotes, so you always know where every dollar goes. Plus, we’ll walk you through financing options that make your project more accessible.

Permits for ADU Construction in San Mateo – What You Need to Know

Navigating the permitting process in San Mateo can be complex—but with Royalty Builders, you won’t have to handle it alone. We’re highly experienced in working with the San Mateo Building Department and understand the local zoning requirements, utility codes, and building standards.

Whether you’re in a single-family or multi-family zone, we’ll ensure your ADU meets all the latest California and city-level ADU regulations—including size restrictions, setbacks, parking allowances, and fire safety standards.

We’ll handle:

• Permit applications and plan submittals

• Coordination with city inspectors

• Responses to plan check comments

• Final approvals and occupancy sign-off

Our team makes it easy to get your project approved quickly and smoothly—so you can break ground sooner.

Why Build an ADU in San Mateo?

San Mateo is a vibrant, diverse city in the heart of the Bay Area that offers an exceptional quality of life, top-rated schools, walkable neighborhoods, and convenient access to major employers in San Francisco and Silicon Valley. But with rising housing demand and limited space, homeowners are looking for creative ways to make the most of their property—and building an ADU is one of the smartest choices.

An Accessory Dwelling Unit gives San Mateo homeowners the ability to:

• Create a private living space for aging parents or young adult children

• Generate rental income to offset mortgage or living costs

• Add a guest house, home office, or creative studio

• Boost property value with a flexible, self-contained structure

With California’s updated ADU-friendly laws and the city’s support for smart infill housing, now is the perfect time to maximize your lot and invest in the future—while enhancing your everyday lifestyle.

Why Choose Royalty Builders for Your San Mateo ADU?

When it comes to building an ADU, you need a team that knows more than just how to pour concrete—you need experts in Bay Area permitting, design efficiency, and residential construction. Royalty Builders brings all of that, and more.

Here’s what sets us apart:

• ✅ Local Experience: We know San Mateo zoning and building regulations inside and out.

• ✅ Design-Build Efficiency: One team manages your entire project from start to finish.

• ✅ Transparent Pricing: No hidden fees or cost surprises—ever.

• ✅ Customization: We don’t build cookie-cutter ADUs. Every project reflects your goals and taste.

• ✅ High-End Craftsmanship: We use quality materials, licensed professionals, and the best construction practices.

• ✅ Rave Reviews: Our clients consistently recommend us for our integrity, responsiveness, and results.

With Royalty Builders, you’re not just building an ADU—you’re investing in peace of mind.

Frequently Asked Questions – ADU Services in San Mateo

Q: How long will it take to build my ADU?
A: Timelines vary, but most projects take between 6–10 months from initial design to final inspection.

Q: Can I rent out my ADU legally?
A: Yes. San Mateo allows ADUs to be rented long-term. We’ll ensure your unit is fully compliant with rental regulations.

Q: Do I need parking for my ADU?
A: In many cases, no! New state laws ease parking requirements for ADUs, especially near public transit.

Q: Can I build more than one ADU?
A: In some zoning cases, yes—you may be able to build both a standard ADU and a Junior ADU. We’ll help assess your eligibility.

Contact Royalty Builders – Your San Mateo ADU Experts

Ready to bring your ADU vision to life? Let’s talk.

At Royalty Builders, we believe every successful project begins with a conversation. Whether you’re still exploring your options or have a clear idea of what you want, we’re here to answer questions, explain your options, and guide you every step of the way.

📞 Call us today and schedule your free ADU consultation in San Mateo.

Let’s build something extraordinary—together.