#1 ADU Contractor in Los Alamitos
Custom Builds by Horizon Remodeling
Horizon Construction & Remodeling Inc. builds accessory dwelling units and home additions throughout Los Alamitos, managing the full project from design and budgeting through permit submittals to the City of Los Alamitos Building and Safety Division and final construction. Many homes here are postwar ranch-style tract homes built between the late 1940s and the 1960s, and we work regularly with that existing footprint to add detached backyard units, attached suites, or garage conversions that meet current building code requirements. Contact us to request a free estimate.
Services We Offer
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.
Read More →
Finding the right adu contractor in Los Alamitos starts with understanding what state law actually allows and how the local permit process works. California ADU law, codified in Government Code sections 66310 through 66342, was updated effective January 1, 2026. Square footage is now measured as interior livable space, and the reviewing agency has 15 business days to determine whether an application is complete, then 60 days to approve or deny it. Approval is ministerial, meaning no public hearing and no discretionary design review stands between you and a decision.
For a property here, that application goes to the City of Los Alamitos Building and Safety Division within the Development Services Department. No unusual local overlay applies, so the building code and any applicable association rules are what govern the project. That keeps the process relatively straightforward compared to cities with additional local restrictions layered on top of state requirements.
The lot itself drives most of the practical decisions. Los Alamitos was built out largely between 1947 and the late 1960s in postwar subdivisions, with the city incorporating in March 1960. The typical home is a single-story ranch tract house with a compact kitchen separated from the living room, and that floor plan shapes where a detached unit can sit, how far utilities have to run, and whether a garage conversion or a new detached build makes more sense. We walk the parcel and check setbacks, grade, equipment access, and utility routes before drawing anything.
State law sets a firm floor on what a local agency can require. A jurisdiction 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. Side and rear setbacks cannot exceed four feet. Owner-occupancy cannot be required as a condition of building an ADU. Construction of the unit cannot trigger a fire sprinkler retrofit of the main house. And there are no impact fees on a unit of 750 square feet or less.
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 Alamitos ?
Horizon Construction and Remodeling is a licensed Class B general building contractor, bonded, and in business since 2009. Our office is in Fullerton, making Los Alamitos a straightforward drive for our project team. A detached ADU is essentially a small house built on a lot that already has a primary residence: foundation, framing, roof, electrical, plumbing, a kitchen, and a bathroom all have to come together as a coordinated whole.
That coordination is where design-build matters most. One company handles the drawings, submits to the City of Los Alamitos Building and Safety Division, and carries the project through construction. If an HOA is involved, we prepare that submittal alongside the building permit application rather than treating it as an afterthought. Because no unusual local overlay applies here, the building code and any association rules are the governing standards we work within from day one.
The postwar ranch homes found in neighborhoods like Carrier Row, Los Alamitos Terrace, College Park North, and Dutch Haven often sit on lots that can accommodate a detached ADU without significant site complications. We also serve nearby communities including Rossmoor, Cypress, and La Palma.
Schedule a Consultation
ADU Contractor Services in Los Alamitos
View Our ADU Contractor Areas of Service
ADU Contractor in Los Alamitos FAQ
What is an ADU and why should I build one?
An accessory dwelling unit is a self-contained secondary home on your property, built as a backyard cottage, a garage conversion, or an in-law suite. Adding one lets you generate rental income, house a family member independently, or simply gain usable square footage, and on the postwar ranch lots common throughout Los Alamitos neighborhoods like Carrier Row and Dutch Haven, there is often room to make it work.
How much does it cost to build an ADU in California?
ADU costs in Los Alamitos depend on details no contractor can assess from a distance. The unit type matters, whether you are converting an existing structure on one of the city’s postwar ranch lots or building a new detached unit from the ground up. The size of the unit, the finish level you choose, and the utility runs your specific parcel requires all move the number in different directions. We walk the property, confirm setback conditions and utility connections, and then give you a fixed scope and price you can hold us to. Anyone quoting a firm number before doing that site work is guessing.
Understanding where the money goes helps you plan. State law exempts ADUs of 750 square feet or less of interior livable space from impact fees, and school fees apply only above 500 square feet. Because the City of Los Alamitos Building and Safety Division processes permits under standard state and local building code with no unusual local overlay complicating the process, the rules are relatively straightforward. Connection fees for a conversion or junior ADU are limited because the state does not classify those as a new residential use. Adding an ADU also cannot trigger a fire sprinkler retrofit of your main house. One caution worth stating plainly: the CalHFA ADU grant program is closed and fully allocated, and the agency itself warns that anyone offering to secure an ADU grant for you is running a scam.
Do I need permits for an ADU in Los Alamitos?
An ADU always requires a building permit, but the approval process is ministerial rather than discretionary, meaning there is no public hearing and no design review board to satisfy. In Los Alamitos, applications go to the Building and Safety Division within the Development Services Department. State law gives the agency 15 business days to confirm completeness and 60 days to approve or deny, though a pre-approved plan shortens that review window to 30 days. We prepare and submit the full permit package and carry it through every inspection, so the process never lands back in your lap.
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 Alamitos?
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 Los Alamitos Building and Safety Division, and construction from start to finish, keeping your project code-compliant and on budget across the postwar ranch neighborhoods that make up most of the city.
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? Reach out to us for a free consultation, where we assess your property, talk through your goals, and put together a detailed estimate with design recommendations, then guide you through every phase of your Los Alamitos 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.
Explore More in Los Alamitos
Horizon is a licensed Class B general building contractor serving Los Alamitos and the surrounding Orange County communities.
Other Services in Los Alamitos
ADU Contractors Nearby
Related Posts About ADU
