#1 ADU Contractor in Los Angeles County
Custom Builds by Horizon Remodeling
Need more space or searching for an ADU contractor near Los Angeles County? Horizon specializes in seamless home additions and custom ADU construction in Los Angeles County, from extra bedrooms to backyard cottages and detached units. As your trusted ADU contractor near Los Angeles County, we manage design, budgeting, permits, and material selection—ensuring every project meets city codes and your vision. Our promise: safety, satisfaction, and a smooth build from start to finish. Let’s turn your ADU and home expansion dreams into reality.
SERVICES WE OFFER
Room Additions
Sunroom Additions
Garages & Conversions
Extensions
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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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California moved its ADU law in 2024 — the rules now live in Government Code sections 66310 through 66342, not the old section 65852.2 — and it changed again on January 1, 2026. Two of those changes matter on nearly every project: square footage limits are now measured as interior livable space, and an agency has 15 business days to tell you whether your application is complete and 60 days to approve or deny it. Approval is ministerial, with no hearing and no discretionary design review.
In unincorporated Los Angeles County that process runs through County Public Works, Building and Safety and the EPIC-LA portal, and the county publishes three free pre-approved ADU plans — an 800 square foot one-bedroom and two 1,200 square foot plans. In any of the county’s 88 cities, the city is your agency instead.
One Los Angeles specific is worth knowing. The county’s ADU ordinance, amended in July 2025, was found non-compliant with state law by the California Department of Housing and Community Development in December 2025 — among other findings, the county caps detached ADUs on a multifamily lot at two where state law allows up to eight. Where the two conflict, state law controls, and that is not something a homeowner should have to argue at a counter alone.
Households rebuilding in unincorporated Los Angeles County after the January 2025 Eaton and Palisades fires should also know the county approved permit fee deferrals and refunds covering plan review, permit and inspection fees, and that ADUs qualify — including where the ADU or garage was the only structure lost. Eligibility rules apply, and we check them with you.
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 Los Angeles County ?
Horizon Construction & Remodeling builds ADUs as a licensed Class B general building contractor, CSLB #938230, bonded and insured, with more than 15 years of design-build work behind us. One company draws the plan, runs it through the agency, and builds it.
On a Los Angeles County ADU the hard part is usually the site rather than the structure — grade, equipment access, where the utilities run, and whether the parcel sits in a very high fire hazard severity zone. We work that out before drawings, because a plan that ignores it becomes a redesign. And where state law and the county ordinance disagree, we know which one governs and we cite it in the submittal.
You can also count on the protections the statute gives you: no owner-occupancy requirement for an ADU, no fire sprinkler retrofit of the main house triggered by building one, and no impact fees on a unit of 750 square feet or less of interior livable space.
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ADU Contractor Services In Los Angeles County
ADU cities we serve in Los Angeles County
ADU Contractor in Los Angeles County FAQ
What is an ADU and why should I build one?
An ADU, or Accessory Dwelling Unit, is a secondary housing unit built on your property—like a backyard cottage, garage conversion, or in-law suite. Building an ADU with Horizon Remodeling allows you to expand your living space, create a rental income opportunity, or provide independent living space for family members.
How much does it cost to build an ADU in California?
The honest answer is that it depends on things we cannot know from a web page: the size and type of unit, whether it is a conversion or new detached construction, the site work and utility runs your lot needs, and the finish level you choose. What we can tell you is where the money goes and what the law protects you from. An ADU of 750 square feet or less of interior livable space is exempt from impact fees; school fees apply only above 500 square feet; and connection fees for a conversion or a junior ADU are limited, because the state does not treat those as a new residential use. Building an ADU also cannot trigger a fire sprinkler retrofit of your main house. Anyone quoting a firm price before seeing the parcel is guessing — we walk the property, confirm the utility and setback situation, and then give you a fixed scope and price you can hold us to.
One warning worth repeating: the CalHFA ADU grant program is closed, its funding fully allocated, and the agency itself warns that anyone offering to help you obtain an ADU grant is running a scam.
Do I need permits for an ADU in Los Angeles County?
Yes — an ADU always requires a building permit, but approval is ministerial rather than discretionary, so there is no hearing and no design review. In unincorporated Los Angeles County the application goes to County Public Works, Building and Safety through the EPIC-LA portal; inside any of the 88 incorporated cities it goes to that city. The agency has 15 business days to tell you whether the application is complete and 60 days from a complete application to approve or deny, and a denial has to identify the specific deficiencies and how to cure them. Horizon submits and manages that process; we do not hand it back to the homeowner.
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 Los Angeles County?
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 15 years of experience delivering high-quality ADU projects.
What are the benefits of hiring Horizon Remodeling for my ADU project?
By choosing Horizon Remodeling, you gain a partner with expertise in ADU design, permitting, and construction. We manage the entire process from start to finish, ensuring your ADU meets building codes, stays within budget, and is completed on schedule.
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?
Contact Horizon Remodeling to schedule a free consultation. We’ll assess your property, discuss your goals, provide design recommendations, and deliver a detailed estimate. From there, our team guides you step-by-step through every phase of your ADU project.
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