#1 ADU Contractor in Irvine
Custom Builds by Horizon Remodeling
Horizon Construction & Remodeling Inc. builds accessory dwelling units and room additions for homeowners across Irvine, handling design coordination, permitting through the City of Irvine Building and Safety Division, and construction across every trade the project requires. Because many Irvine villages operate under homeowners association architectural review, we account for those approval steps early so they do not stall your schedule. Our work as an ADU contractor in Irvine covers detached backyard units, garage conversions, and attached additions on the stucco tract homes and condominiums that make up most of the city’s housing stock.
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How Our ADU Process Works
When it comes to enhancing your living space, room additions combined with Accessory Dwelling Unit (ADU) construction offer unparalleled versatility and value. These projects not only increase square footage but also provide additional living accommodations, whether for extended family, rental income, or work-from-home setups, making them a popular choice for homeowners seeking to maximize their property’s potential. According to California’s Department of Housing and Community Development, ADUs are a key solution to expanding housing options in urban and suburban neighborhoods.
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Working with an adu contractor in Irvine means understanding a permit process and a property landscape that differ from most other Southern California cities. California ADU law, codified in Government Code sections 66310 through 66342 and updated as of January 1, 2026, gives the City of Irvine Building and Safety Division 15 business days to determine whether a submitted application is complete and 60 days to approve or deny it. Approval is ministerial, meaning no public hearing and no discretionary design review stands between your application and a decision.
State law also sets firm protections for property owners. A local agency cannot cap an ADU below 850 square feet of interior livable space, or 1,000 square feet for a unit with more than one bedroom, and square footage is now measured as interior livable space under the 2026 update. Side and rear setbacks cannot exceed four feet, owner-occupancy cannot be required, building an ADU cannot trigger a fire sprinkler retrofit of the primary house, and there are no impact fees on a unit of 750 square feet or less.
Irvine’s master-planned origins shape what is physically possible on any given parcel. The city grew from the late 1960s onward under the William Pereira and Irvine Company plan, incorporating in 1971 with new villages still being added today. Most homes are stucco tract houses or attached condominiums on slab foundations inside themed villages. Floor plans from the 1970s and 1980s typically kept the kitchen closed off, while 2000s and later plans opened it to a great room, and that layout difference affects where a detached unit can realistically sit, how far utility lines must run, and whether a garage conversion or a new detached build makes more practical sense.
Two Irvine-specific factors belong on your checklist before drawings begin. Most villages are governed by a homeowners association with architectural review, which runs on its own timeline separate from the city permit process. Villages developed from the 1980s onward frequently carry Mello-Roos assessments that can affect financing. We walk each parcel to check setbacks, grade, equipment access, and utility routes before any plans are drafted, so that the application submitted to Building and Safety reflects what the lot can actually support.
Other Remodeling Services We Offer
A modern kitchen adds functionality, comfort, and lasting value to your home. At Horizon Construction & Remodeling, our kitchen remodeling experts bring fresh ideas and professional project management tailored to your unique needs. From layout design to material selection, we prioritize delivering a high-standard kitchen that’s both beautiful and energy-efficient — enhancing the way you cook, gather, and live every day.
Whether you envision a classic Southern California pool or a fully customized backyard oasis, Horizon Construction & Remodeling delivers the highest level of quality and service. Our comprehensive pool design and remodeling services cover everything from layout and decking to built-in BBQs and final touches like landscaping. Let Horizon be your trusted partner in transforming your backyard into the perfect outdoor retreat.
If you are planning a complete bathroom remodel or simply want to change your tub, shower, update your plumbing fixtures, or make the space more efficient, our team at Horizon will help you through the process with expert advice, professional craftsmanship, and affordable options with beautiful results. Learn more about our bathroom remodeling services.
Transform your space with our expert interior work services. We offer a comprehensive range of solutions — from space planning and custom design to the selection of high-quality finishes and materials. Our team of experienced professionals works closely with you to create a space that’s both functional and stylish, tailored to your unique needs, goals, and budget. Whether you’re updating a single room or overhauling your entire interior, we bring precision, creativity, and craftsmanship to every project.
At Horizon, we believe your home is more than just four walls — it’s where life happens. It’s the place you relax, gather with family and friends, and create lasting memories. That’s why we offer a full range of exterior work services designed to elevate your outdoor living space. From patios and hardscaping to custom decks and exterior renovations, we help turn your vision into a dream yard that complements your lifestyle and enhances curb appeal.
At Horizon Construction & Remodeling, our expert team includes a dedicated design and planning division that works hand-in-hand with licensed architects and structural engineers. We take care of everything — from detailed plans and blueprints to securing city permits — so you don’t have to deal with delays or red tape. Our goal is to streamline the process and provide a fully approved set of documents that aligns with both your vision and city regulations, saving you time and stress.
Why Choose Horizon Remodeling As Your ADU Contractor in Irvine ?
Horizon Construction and Remodeling is a licensed Class B general building contractor, bonded, and in business since 2009. Our office is in Fullerton, which puts Irvine well within our regular working area rather than an outlying job. We build detached ADUs from the ground up, coordinating every trade involved, including foundation, framing, roofing, and the plumbing and electrical portions handled by appropriately licensed subcontractors we manage directly.
Irvine’s master-planned villages bring a layer of process that matters from day one. Most neighborhoods carry homeowners association architectural review requirements, and in villages developed from the 1980s onward, Mello-Roos assessments are common. We prepare HOA submittals alongside the City of Irvine Building and Safety Division permit application rather than treating them as separate steps, which keeps the project moving.
A detached ADU is essentially a small house placed on a lot that already has a primary residence. Design decisions and construction constraints are the same decisions, so having one company draw, permit, and build the unit avoids the gaps that open up when those responsibilities are split. We work throughout Irvine, including Woodbridge, Turtle Rock, University Park, and Westpark.
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ADU Contractor Services in Irvine
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ADU Contractor in Irvine FAQ
What is an ADU and why should I build one?
An accessory dwelling unit is a self-contained secondary residence on your property, taking the form of a converted garage, a detached backyard structure, or an attached in-law suite. Building one with Horizon Construction and Remodeling can open up rental income, give a family member independent living space, or simply add usable square footage to your Irvine home.
How much does it cost to build an ADU in California?
Pricing an ADU in Irvine depends on details no contractor can know before visiting your property: the unit size, whether you are converting an existing structure or building new detached construction, what site work and utility runs your specific lot requires, and the finish level you have in mind. Because many Irvine villages are governed by a homeowners association with an architectural review process, that layer of approval can also affect the scope and schedule of your project. We walk the parcel, confirm setbacks and utility conditions, and give you a fixed scope and price you can hold us to. Anyone quoting firm numbers before doing that is guessing.
State law does provide meaningful cost protections worth knowing. An ADU with 750 square feet or less of interior livable space is exempt from impact fees. School fees apply only to units above 500 square feet. Connection fees for a conversion or junior ADU are limited because the state does not classify those as a new residential use, and adding an ADU cannot force a fire sprinkler retrofit on your main house. Permits in Irvine run through the City of Irvine Building and Safety Division, which we coordinate directly. One important warning: the CalHFA ADU grant program is closed and fully allocated, and the agency itself states that anyone offering to help you obtain an ADU grant is running a scam.
Do I need permits for an ADU in Irvine?
Yes, a building permit is always required for an ADU, but state law makes approval ministerial rather than discretionary, meaning there is no public hearing and no design review board to satisfy. In Irvine, applications go to the City of Irvine Building and Safety Division, which has 15 business days to confirm a submittal is complete and 60 days to approve or deny it. Using a pre-approved plan shortens that review window to 30 days. Horizon prepares and submits the full permit package and stays with the project through every required inspection, so the process never falls back on you.
How long does ADU construction take with Horizon Remodeling?
Most ADU construction projects take between 4 to 8 months from design to completion, depending on scope and permit approvals. Horizon Remodeling prioritizes efficient timelines while maintaining quality workmanship.
What types of ADUs can Horizon Remodeling build?
We specialize in building detached ADUs, attached ADUs, garage conversions, backyard cottages, and junior ADUs (JADUs). Our team can help you choose the right ADU style for your property and goals.
Can I build a detached ADU on my property in Irvine?
Yes, if your property meets California zoning and space requirements. Horizon Remodeling will assess your site, secure the necessary permits, and build a fully detached ADU tailored to your preferences.
Is Horizon Remodeling licensed to build ADUs in my area?
Yes, Horizon Remodeling is fully licensed, bonded, and insured to build ADUs throughout Orange County and surrounding areas. We have over 18 years of experience delivering high-quality ADU projects.
What are the benefits of hiring Horizon Remodeling for my ADU project?
Horizon Construction & Remodeling Inc. handles ADU design, permitting through the City of Irvine Building and Safety Division, and construction from start to finish, coordinating every trade so your project stays on budget and meets current building codes.
Does Horizon Remodeling handle ADU design and permitting?
Absolutely! Horizon Remodeling provides complete ADU design services, including architectural plans and 3D renderings. We also handle city permits and inspections, streamlining your project and reducing stress.
How do I get started on an ADU with Horizon Remodeling?
Ready to move forward? Reach out to us for a free consultation, where we assess your Irvine property, talk through your goals, share design recommendations, and put together a detailed estimate before walking you through every phase of your ADU project.
Recent ADU and Garage Conversions
Three completed ADU and garage conversion projects from our Orange County portfolio. Every project below was built in San Clemente. Nothing loads from YouTube until you press play.
ADU project in San Clemente
ADU project in San Clemente
ADU project in San Clemente
Built by Horizon Construction & Remodeling, Inc. Licensed Class B general building contractor.
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Horizon is a licensed Class B general building contractor serving Irvine and the surrounding Orange County communities.
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