#1 ADU Contractor in Orange
Custom Builds by Horizon Remodeling
Horizon Construction & Remodeling Inc. builds accessory dwelling units and home additions throughout Orange, handling design coordination, permitting through the City of Orange Community Development Department, material selection, and construction under one general contract. Orange presents a range of site conditions, from early twentieth century Craftsman bungalows and revival-era houses in the Plaza Historic District to postwar tract homes and Eichler properties with their post-and-beam ceilings, and projects in Old Towne or the Eichler tracts may require design review under the city’s historic preservation or Eichler design standards before a permit is issued. We coordinate every trade involved so the finished unit meets current code and works with your existing property.
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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 as your adu contractor in Orange means understanding a regulatory picture that has two distinct layers. California ADU law, codified in Government Code sections 66310 through 66342 and updated effective January 1, 2026, sets a statewide floor of rights that no local agency can take away. Under those rules, approval is ministerial, meaning no public hearing and no discretionary design review, and the city has 15 business days to determine whether your application is complete and 60 days to approve or deny it. That application goes to the City of Orange Community Development Department.
State law also fixes several protections regardless of where your parcel sits. A local agency cannot cap an ADU below 850 square feet of interior livable space, measured as livable area under the 2026 update, or below 1,000 square feet if the unit has more than one bedroom. Side and rear setbacks cannot exceed four feet, owner-occupancy cannot be required, building the ADU cannot trigger a sprinkler retrofit of the main house, and there are no impact fees on units of 750 square feet or less.
Orange adds a second layer that matters on certain parcels. Old Towne, the largest National Register historic district in California since its 1997 listing, operates under Historic Preservation Design Standards that govern exterior changes, and the Eichler tracts carry their own Orange Eichler Design Standards. Both require design review for exterior work, which affects how we approach detached builds on those lots.
The housing stock shapes the conversation everywhere else. Orange grew from a core of early twentieth century bungalows and Craftsman houses dating to the period between 1886 and 1935, then added postwar tract subdivisions through the early 1970s, including the open-plan Eichler homes with their post and beam ceilings. That mix means utility runs, setbacks, grade, and equipment access vary considerably from one parcel to the next, so we walk the lot and review all of that before a single line gets drawn.
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 Orange ?
ADU Contractor in Orange, CA
Horizon Construction and Remodeling is a licensed Class B general building contractor, bonded, and based in Fullerton, which puts Orange just a short drive from our office. We have been doing this work since 2009, and a detached ADU covers every major building trade at once: foundation, framing, roof, electrical service, plumbing, a kitchen, and a bathroom set on a lot that already has a primary house on it.
Permits for ADU projects in Orange go through the City of Orange Community Development Department. If your property sits within Old Towne or one of the Eichler tracts, exterior work also moves through design review under the Historic Preservation Design Standards or the Orange Eichler Design Standards. We prepare those submittals alongside the building permit so nothing waits on the other.
Keeping design and construction under one contractor matters on an ADU because the decisions that shape the drawings are the same ones that drive cost and schedule on the job site. We work throughout Orange, including Old Towne, the Plaza Historic District, Fairhaven, and Fairhills.
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ADU Contractor Services in Orange
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ADU Contractor in Orange FAQ
What is an ADU and why should I build one?
An accessory dwelling unit is a self-contained secondary residence built on your existing property, taking the form of a converted garage, a detached backyard cottage, or an attached in-law suite. Adding one to your Orange home can generate rental income, house extended family, or simply give you more usable space, though properties in Old Towne or the Eichler tracts typically face additional design review before permits are issued through the City of Orange Community Development Department.
How much does it cost to build an ADU in California?
ADU costs in Orange depend on details no contractor can assess from a distance: whether you are converting an existing structure or building a new detached unit, how much site and utility work your specific lot requires, and what finish level you want inside. What state law does establish are a few concrete protections worth knowing before you budget. An ADU at or under 750 square feet of livable space is exempt from local impact fees. School fees only apply above 500 square feet. Connection fees for a junior ADU or a garage conversion are capped because the state does not classify those as a new residential use, and adding an ADU cannot force a fire sprinkler retrofit on your existing home. These rules apply city-wide, including properties going through the City of Orange Community Development Department.
Orange adds local layers that directly affect cost and timeline. Homes in the Plaza Historic District and Old Towne, the largest National Register historic district in California, face Historic Preservation Design Standards that govern exterior changes and require design review. The Eichler tracts carry their own Orange Eichler Design Standards. Both sets of rules can shape what materials and configurations are approvable. Any contractor quoting a firm number before walking your parcel and confirming setbacks, utility access, and applicable design standards is working from assumptions, not facts. One warning worth repeating: the CalHFA ADU grant program is closed and fully allocated, and the agency itself states that anyone offering to help you obtain that grant is running a scam.
Do I need permits for an ADU in Orange?
Yes, an ADU always requires a building permit, though approval is ministerial rather than discretionary, meaning no public hearing and no design review panel for standard ADU applications. In Orange, that application goes to the City of Orange Community Development Department, which has 15 business days to confirm completeness and 60 days to issue a decision, a window that drops to 30 days when a pre-approved plan is used. We prepare and submit the full package and carry it through every inspection so you are not left managing the process yourself.
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 Orange?
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. manages every stage of your ADU project in Orange, from initial design through City of Orange Community Development Department permitting and final construction, keeping the work code-compliant and the budget on track, including design review requirements that apply in Old Towne and the Eichler tracts.
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 get started on an ADU in Orange? Contact us to schedule a free consultation, where we assess your property, talk through your goals, and deliver a detailed project estimate. If your home sits in Old Towne or an Eichler tract, we factor in the city’s design review requirements from the start. We guide you through every phase, step by step.
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 Orange and the surrounding Orange County communities.
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