Home Additions & Structural Renovations in Orange County

Your Home's Living Space, Expanded.

Imagine a spacious new master suite, a family room that seamlessly flows into your backyard, or a second story that captures breathtaking views. A home addition or major structural renovation is the ultimate way to tailor your home to your evolving lifestyle without leaving the neighborhood you love. At Sanctuary Design & Build, we specialize in the complex art and science of expanding and reconfiguring homes, creating spaces that are both beautiful and structurally sound.

As Orange County's trusted general contractor for major renovations, we know that homeowners from Irvine to Newport Beach are seeking a partner to navigate this significant undertaking. You're not just adding square footage; you're making a profound investment in your family's future. Whether your search was for "home addition contractor Orange County" or "ADU builder Irvine," you've found a team with the expertise to manage your project from architectural design to final inspection.

Expanding or reconfiguring your home is a transformative process. To help you understand the possibilities, we've organized our expertise into the following distinct Project Types. Each represents a significant investment in your home's space, function, and value.

Single & Multi-Room Home Additions: Designing and building new, seamlessly integrated spaces, such as a family room expansion, a new master suite, or a multi-room wing.
Second-Story Addition: The complex process of adding a new level to an existing single-story home, effectively doubling your living space on the same footprint.
Accessory Dwelling Unit (ADU) Construction: Complete design and build of detached or attached ADUs (also known as granny flats or casitas), perfect for multi-generational living or rental income.
Garage Conversion to Living Space / ADU: Expertly converting an existing garage into a fully conditioned, habitable living space or a legally permitted Accessory Dwelling Unit.
Major Interior Structural Reconfiguration: Significant alterations to your home's layout, including the engineering and removal of load-bearing walls to create modern, open-concept living areas.

And more, including Foundation Repair & Seismic Retrofitting to enhance structural integrity.

Our design process ensures that every addition or alteration feels as though it was part of the original home. Whether you envision a modern addition with clean lines, a traditional expansion that matches your home's historic character, or a functional ADU designed for independent living, our team specializes in creating spaces that perfectly meet your family's needs.

Explore Our Services & Styles

image of a newly completed single-room home addition with large windows and sliding glass doors, seamlessly integrated into a Southern California residential house, bathed in natural light. The quality craftsmanship of the mid-to-high-end residential project in Orange County is clearly highlighted, with authentic, natural landscaping in the foreground.

Single & Multi-Room Home Additions

Second-Story Addition

image of a newly constructed, detached accessory dwelling unit (ADU) with modern design, large windows, and a small patio, set in a sunny Orange County residential backyard with mature landscaping. The ADU showcases quality craftsmanship as a mid-to-high-end home addition.

Accessory Dwelling Unit (ADU) Construction

image of a garage converted into a bright, contemporary ADU in Orange County, featuring large windows and French doors opening to a lush Southern California garden, showcasing a high-quality residential renovation.

Garage Conversion to Living Space / ADU

image of a bright, open-concept living space in a Southern California residential home, showcasing a newly configured kitchen and living room after a major structural renovation. The image highlights the seamless flow between areas with natural light, modern kitchen elements, and comfortable living room furnishings, reflecting a mid-to-high-end transformation while maintaining a realistic, lived-in feel with existing architectural details.

Major Interior Structural Reconfiguration

image of a completed foundation repair and seismic retrofitting on a residential home in Orange County, California. The image showcases the structural improvements, blending seamlessly with the mid-to-high-end Southern California architectural style, under bright natural light. The surrounding landscape and existing parts of the house appear naturally aged, highlighting the quality craftsmanship of the newly reinforced structure without an artificial, perfect look.

Foundation Repair & Seismic Retrofitting

We believe a successful addition is one that is indistinguishable from the original structure. Our reputation is built on a foundation of trust, meticulous engineering, and an unwavering commitment to our clients.

Unmatched Local Expertise: Our deep understanding of Orange County's complex permitting processes, zoning ordinances, and specific requirements for ADUs and additions ensures your project is designed for approval and built to code.
An Unwavering Commitment to Craftsmanship: We stand behind our work. Our reputation is built on superior foundation work, precise framing, and the art of seamlessly blending new construction with your existing home, from the roofline down to the flooring.
An Investment in Your Home's Future Value: A well-designed addition or ADU is a direct investment in your property's square footage and functionality—the most significant drivers of value in the Orange County real estate market.
Designs that Transform Your Lifestyle: Beyond property value, we create spaces that fundamentally change how you live. An addition can provide a needed bedroom for a growing family, an ADU can bring loved ones closer, and an open-concept renovation can transform your home into an entertainer's dream.

The Sanctuary Difference

4 panel collage of our consultation, design, construction and completed project process showing all a collaborated design to build process

Our Commitment to a Superior Remodeling Experience

Expert Guidance

Empower your architectural design choices with exclusive access to our Lumina educational hub and structural design studio.

Peace of Mind

Enjoy lasting confidence in your new addition, protected by our comprehensive Sanctuary Care workmanship warranty.

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Our Proven Process

Discover our transparent, step-by-step design-build process that ensures a structurally sound and seamless addition from concept to completion.

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Our Trusted Team

Meet the veteran, family-owned specialists in home additions and structural engineering, fully licensed and insured for your peace of mind.

"How much does a home addition cost per square foot in Orange County?"
- The cost varies significantly based on complexity (a simple room vs. a kitchen or bath). You can expect a range from $350 to over $600 per square foot. Second-story additions are typically more complex and fall at the higher end of that range.
"What is the difference between converting my garage and building a legal ADU?"
- A simple conversion might create a bonus room, but a legal ADU is a separate, rentable dwelling unit with its own kitchen, bathroom, and entrance. Building a legal ADU involves a more complex permitting process but significantly increases your property's value and utility.
"How long does it take to build a second-story addition?"
- This is a major undertaking. From the start of design to the completion of construction, a second-story addition typically takes 9 to 12 months, including the extensive time required for architectural plans, engineering, and city plan review.
"What is involved in removing a load-bearing wall?"
- It requires a structural engineer to design a new support system, typically a large beam (often hidden in the ceiling) and new support posts, to carry the load that the wall was supporting. This is not a DIY project and requires professional engineering and construction.

Your journey to a larger, more functional, and more valuable home starts with a simple conversation. Let's begin the process of creating the space your family has always dreamed of.