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#1 ADU Contractor in Manhattan Beach
Custom Builds by Horizon Remodeling

Horizon Construction & Remodeling Inc. builds accessory dwelling units and home additions for homeowners in Manhattan Beach, managing design, budgeting, permits through the City of Manhattan Beach Community Development Department Building and Safety Division, and material selection from start to final walkthrough. Projects range from backyard cottages and detached units to additional bedrooms, and every scope is handled with attention to city code requirements. On Sand Section lots that front walk streets and alleys, we plan material staging and site access carefully from the beginning so work stays on track.

Services We Offer

Room Additions​

Sunroom Additions​

Garages & Conversions​

Extensions​

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.

Finding the right adu contractor in Manhattan Beach means working with a team that understands both state law and the specific physical realities of a city built out on narrow beach town lots over a century ago. California consolidated its ADU statutes into Government Code sections 66310 through 66342 in 2024, and those rules changed again on January 1, 2026. Square footage is now measured as interior livable space. Once you submit an application, the reviewing agency has 15 business days to determine whether it is complete and 60 days to approve or deny it. Approval is ministerial, meaning no public hearing and no discretionary design review.

In Manhattan Beach, that application goes to the City of Manhattan Beach Community Development Department Building and Safety Division, not a county office. That distinction matters because Los Angeles County contains 88 incorporated cities, and the agency receiving your paperwork changes from one city to the next even when the underlying state rules do not. The county’s own 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, it caps detached ADUs on a multifamily lot at two where state law allows up to eight. That ordinance covers unincorporated territory rather than incorporated cities like Manhattan Beach, but it is a useful reminder that a local handout is not always current with the statute.

State law does set a floor of protections that applies regardless of where a parcel sits. A local agency cannot cap an ADU below 850 square feet of interior livable space, or below 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. Building an ADU cannot trigger a fire sprinkler retrofit of the main house. There are no impact fees on a unit of 750 square feet or less.

The lot decides most of the practical questions once the legal framework is clear. Manhattan Beach was platted in the early 1900s and built out from its 1912 incorporation onward after the natural sand dunes were leveled during the 1920s and 1930s. The result is a city of narrow beach town lots where homes stack vertically, with kitchens frequently sitting on an upper level rather than at grade. That vertical layout shapes how far utility lines have to run to reach a new detached unit and whether a garage conversion or a new freestanding build is the more workable answer on a given parcel.

Access adds another layer of planning, particularly in the Sand Section, where many blocks front walk streets and alleys rather than conventional driveways. That configuration constrains material staging, equipment movement and parking during construction in ways that a standard suburban job site does not. We walk every parcel before drawing anything, checking setbacks, grade changes, equipment access and utility routes so that the plan we bring to the Building and Safety Division reflects what the site can actually support.

Other Remodeling Services We Offer

Why Choose Horizon Remodeling As Your ADU Contractor in Manhattan Beach ?

Horizon Construction and Remodeling is a Class B general building contractor, licensed and bonded, and we have been doing this work since 2009. We handle ADU contractor work in Manhattan Beach from a single point of contact: one team draws the plans, submits to the City of Manhattan Beach Community Development Department Building and Safety Division, and builds the unit.

On a beach town lot the site almost always drives the project more than the structure does. Manhattan Beach lots are narrow, and in the Sand Section many blocks front walk streets and alleys, which limits where equipment can stage and how materials move in. We sort out access, utility routing, and any fire hazard zone conditions before a line goes on paper, because skipping that step produces a plan that has to be redrawn.

Where state ADU law and local ordinance say different things, we identify which controls and note it in the submittal. That matters in a city with housing stock dating back to the early 1900s, where lot configurations rarely fit a standard approach.

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ADU Contractor Services in Manhattan Beach

ADU Contractor in Manhattan Beach FAQ

What is an ADU and why should I build one?

An accessory dwelling unit is a secondary housing unit added to your existing property, taking the form of a backyard cottage, a garage conversion, or an in-law suite. Building an ADU with Horizon Construction and Remodeling lets you add living space, generate rental income, or give a family member a place of their own, all on the same lot.

What an ADU costs in Manhattan Beach depends on details no contractor can assess from a website alone. The unit size and type matter, as does whether you are converting existing square footage or building a new detached structure. Site work varies lot by lot, and on the narrow parcels that are common throughout the Sand Section and Tree Section, utility runs and material staging can add complexity that a flat quote simply cannot account for. Walk streets and alley-fronting blocks present real access constraints that affect how and when materials arrive. Finish level is another variable. All of those factors shape the final number, and anyone naming a firm price before walking your property is guessing.

What the law does fix are certain fee limits that work in your favor. An ADU at or under 750 square feet of livable space is exempt from impact fees. School fees apply only when the unit exceeds 500 square feet. Connection fees for a conversion or junior ADU are capped because the state does not classify those as a new residential use, and building an ADU cannot force a fire sprinkler retrofit on your main house. Permits run through the City of Manhattan Beach Community Development Department Building and Safety Division. We walk the site, confirm setbacks and utility conditions, and then provide a fixed scope and price. One important warning: the CalHFA ADU grant program is closed and fully allocated, and the agency itself states that any offer to help you obtain that grant is a scam.

An ADU in Manhattan Beach always requires a building permit, though state law makes approval ministerial rather than discretionary, meaning there is no hearing and no design review board to face. Applications go to the City of Manhattan Beach Community Development Department Building and Safety Division, which has 15 business days to confirm completeness and 60 days to approve or deny; any denial must identify the specific deficiencies and explain how to cure them. Using a pre-approved plan shortens that review window to 30 days. We prepare and submit the permit package and carry it through every required inspection, so the process never gets handed back to you.

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.

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.

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.

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.

Horizon Construction & Remodeling Inc. handles ADU design, permitting through the City of Manhattan Beach Community Development Department, and construction as a single coordinated process, keeping the project on budget and built to code, even on the narrow lots and alley-access blocks common across the Sand Section.

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.

Reach out to Horizon Construction & Remodeling Inc. to schedule a free consultation, where we assess your property, talk through your goals, and deliver a detailed estimate covering every phase of your Manhattan Beach ADU project, including design recommendations and guidance from start to finish.

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Horizon is a licensed Class B general building contractor serving Manhattan Beach and the surrounding Orange County communities.