`ADU & Garage Conversions`

ADU Garage Conversions Orange County experts. Maximize your property’s value and living space. From functional garage transformations to fully detached backyard homes, we handle everything from city permits to the final coat of paint.

Our ADU Solutions

As the premier experts in ADU Garage Conversions Orange County, we offer turnkey solutions—from converting existing spaces to building brand new units—tailored to your property and investment goals.

Garage Conversions

Transform your unused garage into a profitable rental unit or a comfortable guest suite. We handle the structural upgrades, Title 24 insulation, and new utility connections required by California code.

Discuss Your Garage Conversion

Detached ADUs (Ground-Up)

Maximize your backyard’s potential with a fully independent home. As a licensed Class B contractor, we manage the entire build: from trenching and pouring the foundation to expert framing and final interior finishes.

Discuss Your ADU Project

Navigating California ADU Laws

Building an ADU in Orange County involves strict zoning laws, setbacks, and Title 24 energy compliance. Coastline Harmony Builders, Inc. simplifies this complex process. We execute your architect’s plans with precision, ensuring your project is fully permitted, legally compliant, and built to the highest structural standards. Whether you are navigating the specific lot requirements of Irvine, Newport Beach, or the surrounding areas, our deep understanding of local municipal codes ensures there are no costly delays. We handle the red tape so you can focus on the incredible value your new unit will bring.

How Our ADU Garage Conversions Orange County Process Works

Step 1 — Site Evaluation & Feasibility

We conduct a detailed audit of your property’s zoning, setbacks, and existing utilities to ensure yourADU Garage Conversions Orange County build meets all local California building codes and density requirements.

Step 2 — Engineering & City Permits

As a licensed Class B contractor, we manage the entire architectural and structural engineering phase. We handle all city submittals and secure the necessary permits for your project to be 100% legal and compliant.

Step 3 — Structural Construction & Utilities

Whether it’s trenching for new sewer lines, upgrading electrical panels, or reinforcing a garage slab, we execute the heavy lifting. We ensure all framing and utility connections are built to the highest structural standards.

Step 4 — Premium Interior Completion

Our turnkey approach finishes with high-end interior work. From insulation and drywall to custom flooring and cabinetry, we transform your unused space into a high-value, livable ADU or rental unit.

Why Homeowners Choose Coastline Harmony Builders

Licensed Authority & Compliance

As a licensed Class B General Contractor in California, we handle the entire regulatory landscape for you. From strict Orange County zoning and setbacks to Title 24 energy compliance, we ensure your project is 100% legal, permitted, and built to the highest safety standards.

True Turnkey Engineering

We don’t just remodel; we build. From structural foundation reinforcements and trenching for new utility lines to advanced HVAC integration and high-end interior finishes, our technical background ensures your garage conversion is built to the highest structural standards of a modern home.

Transparent Local Partnership

Based right here in OC, we pride ourselves on clear communication and fixed-price estimates. No hidden fees or “construction surprises”—just professional, scheduled execution from a local team that understands the Irvine and Newport Beach building landscape.

What Our Clients Say

    
 
 
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   Mira Mingalieva 
 
 
 
 Trustindex verifies that the original source of the review is Google. Absolutely thrilled with our new kitchen! We were looking to update our house in Tustin and decided to go with a dark, modern kitchen design. The team at Coastline Harmony Builders did an amazing job from start to finish. The quality of the custom cabinets is top-notch, with amazing built-in storage and flawless integration of our appliances. Everything feels so premium and sleek. It’s hard to find a trustworthy general contractor, but these guys are the real deal. Highly recommend them for any home renovation!
  
 
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   Lexie 
 
 
 
 Trustindex verifies that the original source of the review is Google. Rafael and his team at Coastline Harmony Builders did an incredible job with our kitchen remodel in Irvine. We wanted a high-end look and they delivered perfectly—from the custom cabinet installation to the countertop and lighting coordination. They are very detail-oriented, professional, and kept everything on track. Highly recommend them if you’re looking for a reliable general contractor in Orange County!
  
 
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   Irina Borovleva 
 
 
 
 Trustindex verifies that the original source of the review is Google. We hired Coastline Harmony Builders for our kitchen remodel in Irvine, and we had a great experience from start to finish. Rafael helped us with the full process, including demolition, site preparation, cabinet installation, appliance panels, backsplash coordination, and the final finish details. We had a modern flat-panel cabinet system, and everything came out clean, aligned, and very high-end. What we appreciated most was the communication, organization, and how clean they kept the house during the remodel. It was clear that Rafael understands both the construction side and the precision needed for cabinet installation. Highly recommend Coastline Harmony Builders for anyone looking for a reliable kitchen remodeling contractor in Orange County.
  
 
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   Sasha Kadik 
 
 
 
 Trustindex verifies that the original source of the review is Google. Coastline Harmony Builders did an amazing job on our home renovation in LA. They completely refreshed our entire house, including a stunning bathroom remodel, but the highlight was definitely the kitchen. We wanted a high-end look, so we ordered IKEA SEKTION boxes and paired them with Semihandmade custom fronts. Rafael and his team handled the complex layout, panel integration, and custom hardware with incredible precision. It’s rare to find a General Contractor who has both the structural expertise for a whole-house refresh and the meticulous attention to detail required for European-style modular cabinetry. Highly recommend them!
  
 
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   Natalia Grechaniuk 
 
 
 
 Trustindex verifies that the original source of the review is Google. Coastline Harmony Builders did a fantastic job on our kitchen and bathroom remodel in Woodland Hills. We were really impressed with their project management and attention to detail. They kept the house super clean during the demo phase, and the final result with the new custom kitchen setup is exactly what we wanted. Great communication from start to finish. Highly recommend!
  
 
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   Анастасія Чорна 
 
 
 
 Trustindex verifies that the original source of the review is Google. Rafael and his team did an amazing job on our kitchen remodel in Huntington Beach. We ordered the BOXI cabinets by Semihandmade and really needed a solid GC to handle the whole project turnkey. Coastline Harmony Builders took care of everything for us, starting from the demo all the way to the final flawless cabinet installation. Super clean, professional, and zero stress. Highly recommend!
  
 
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   Marina Ilyushina 
 
 
 
 Trustindex verifies that the original source of the review is Google. We used Coastline Harmony Builders for our whole house remodel in Mission Viejo and honestly, we couldn’t be happier. We needed a solid general contractor who could handle everything from knocking down walls to giving us our dream kitchen, and they totally delivered. They took care of all the city permits, kept the project on schedule, and the attention to detail is just amazing. The house feels completely brand new. Highly recommend these guys if you have a big project!
  
 
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   Kate Ivanova 
 
 
 
 Trustindex verifies that the original source of the review is Google. We hired Coastline Harmony Builders for a garage conversion project in Newport Beach. Rafael is a highly professional general contractor who managed everything perfectly from start to finish. If you’re looking for a reliable ADU builder in Orange County, look no further!
  
 
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   Ryma Rashytava 
 
 
 
 Trustindex verifies that the original source of the review is Google. Rafael and his team did an awesome job on our bathroom remodel in Irvine. We had an old tub converted into a walk in shower and it looks fantastic. They were professional, kept the house clean, and finished right on time. Highly recommend Coastline Harmony Builders!
  
 
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   Natalia Borzenko 
 
 
 
 Trustindex verifies that the original source of the review is Google. Rafael and his team at Coastline Harmony Builders did an amazing job on our Irvine kitchen remodel. We were a bit stressed about the whole demo and electrical process, but they handled it all so smoothly. The custom cabinet fronts look incredible, and they actually kept the house clean while working. Great communication the whole time. We absolutely love our new kitchen!

ADU & Garage Conversion Service Areas

We provide ADU and garage conversion services throughout Orange County, including Irvine, Costa Mesa, Santa Ana, Anaheim, Huntington Beach, Newport Beach, and nearby communities.
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ADU Garage Conversions Orange County FAQ

Do I need a permit for a garage conversion in Orange County?

Yes, every legal ADU requires building permits. We handle the entire process — from structural plans to final inspections — to ensure your conversion is fully permitted and adds real value to your home. As a specialist in ADU Garage Conversions Orange County, Coastline Harmony Builders ensures your project meets all Title 24 requirements.

How long does it take to build a detached ADU?

A typical ground-up ADU takes 6 to 9 months, while a garage conversion can often be completed in 3 to 4 months. This includes the initial design phase, city approvals, and full construction.

Can I add a kitchen and bathroom to my garage conversion?

Absolutely. As a licensed General Contractor, we specialize in extending utility lines (water, sewer, and electricity) to your garage, creating a fully independent and functional living space.

Will an ADU or garage conversion increase my property taxes and home value?

Adding an ADU Garage Conversions Orange County is a high-return investment that significantly boosts your property’s resale value and potential rental income. Under California law, only the new construction is assessed for property taxes—your primary residence's original tax base remains protected. In the Orange County market, the increase in home equity typically far exceeds the construction costs, making it a smart long-term financial move.

Photography and renderings shown on this page are for illustrative and inspirational purposes, representing the design styles, materials, and quality standard of our turnkey installations.

Ready To Expand Your Property?

From initial site evaluation to flawless construction, trust Coastline Harmony Builders to deliver a high-quality ADU that adds lasting value to your home. Whether you need a functional garage conversion or a fully detached ground-up build, our licensed team is ready to bring your vision to life. Contact us today

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Fully Licensed, Insured & EPA Lead-Safe Certified for your peace of mind.