Detached ADUs, garage conversions, attached ADUs and custom additions—handled by one licensed, insured and bonded design-build team from the initial property evaluation through permits, construction and final inspection.
Licensed • Insured • Bonded • 15+ Years Experience • Design-Build Experts • Serving Southern California
Thinking about building an ADU on your Huntington Beach property? Whether you’re planning a detached backyard ADU, converting an existing garage, adding an attached unit, or creating a separate space for family, guests, or long-term rental use, the first step is understanding what actually works on your lot.
At Kol & Co., we handle the entire project as one design-build team. That means we can evaluate your property, plan the layout, coordinate architectural and engineering requirements, manage permits, build the ADU, and take the project through inspections and final completion.
We work with homeowners throughout Downtown Huntington Beach, Huntington Harbour, Bolsa Chica, Seacliff, Goldenwest, Adams, Garfield, Southeast Huntington Beach, and nearby Huntington Beach neighborhoods. Because every property is different, we look closely at the existing home and garage, available yard space, access, utilities, setbacks, structural conditions, and how you plan to use the ADU before recommending the best direction.
Kol & Co. is a licensed, insured, and bonded California general contractor with 15+ years of construction experience. Our goal is to help you make the right decisions early, so the design, budget, permitting, and construction stay coordinated from the beginning.
Schedule a in-home consultation with Kol & Co. today!
Most full ADU projects we plan for fall around $200,000–$500,000+, depending on the project.
A detached ADU built from the ground up typically has a very different scope from converting an existing garage, and two ADUs of the same square footage can still have very different construction costs.
The biggest cost factors include:
Every project is different, but an ADU Construction may include:
Before construction starts, the ADU needs to be properly planned around your property, budget, and applicable requirements. Our design-build team coordinates the pre-construction process so the plans and construction scope stay aligned.
May include:
Whether we're building a detached ADU or adding onto an existing structure, we handle the major construction needed to create a complete, weather-tight residential building.
May include:
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An ADU is a complete living unit, which means its systems need to be planned along with the structure—not treated as an afterthought. We coordinate the necessary trades and connections throughout construction.
May include:
Once the structure and major systems are complete, we finish the ADU as a functional home. Selections can be tailored to how you plan to use the unit and the level of finish you want.
May include:
ADUs in Huntington Beach are governed by a combination of California ADU law, local development standards, building codes, and property-specific conditions.
Here are the main requirements to know when you’re considering an ADU in Huntington Beach:
Not sure what applies to your property? We can evaluate your lot, existing structures, access, utilities, and ADU goals before developing the plans.
Typical total timeline: Approximately 12 months, including plans, permits, construction, and inspections.
Yes. An ADU requires approved plans, building permits, and inspections before it can legally be completed and occupied. Depending on the project, the plan set may involve architectural plans, structural engineering, Title 24 documentation, utility information, and other project-specific requirements.
As your design-build contractor, Kol & Co. coordinates the process from initial planning through permit issuance and construction.
That means you aren’t left trying to coordinate the designer, engineer, city comments, contractor, and inspections separately.
We visit your Huntington Beach property, discuss what you're trying to build, and evaluate the existing site.
We develop the ADU layout, establish the scope, and coordinate architectural and engineering requirements.
We prepare the required documentation, submit the plans, and coordinate corrections through permit approval.
Our team manages the build from site preparation and foundation through framing, utilities, interior finishes, and exterior work.
We coordinate required inspections, address final items, and walk the completed ADU with you before closeout.
We work with homeowners throughout Huntington Beach, including Downtown Huntington Beach, Huntington Harbour, Bolsa Chica, Seacliff, Goldenwest, Adams, Garfield, Southeast Huntington Beach, and surrounding neighborhoods.
You don’t need to have the floor plan, size, or every finish figured out before talking to us.
If you’re considering an ADU in Huntington Beach, we’ll visit your property, discuss how you want to use the space, look at the existing site conditions, and help you understand the next steps.
From design and engineering through permits, construction, inspections, and completion, you’ll have one design-build team managing the project.
Schedule your in-home consultation and let’s see what makes sense for your property.
An ADU (Accessory Dwelling Unit) is a self-contained residential unit built on the same lot as a primary home. ADUs can be detached backyard units, garage conversions, or attached additions, as long as they meet California and city zoning requirements.
Most full ADU projects we plan for range from approximately $200,000–$500,000+, depending on size, type, utilities, site conditions, finishes, and structural requirements.
Typical total timeline: Approximately 12 months, including plans, permits, construction, and inspections. Complex projects can take longer.
Many residential properties can accommodate an ADU, but the appropriate size, location, and type depend on the lot and proposed project. We evaluate these conditions during the initial planning stage.
A detached ADU can generally be built up to 1,200 sq. ft., depending on the property and project. The allowable size can vary based on the ADU type and applicable state and local requirements.
A standard detached ADU is generally allowed at least 16 feet in height. Certain ADUs and properties may qualify for additional height under California ADU law.
New ADU construction generally has 4-foot side and rear setbacks. Garage conversions and conversions of other legally existing structures may be treated differently.
Yes. ADUs require approved plans, building permits, and inspections. Properties within Huntington Beach’s Coastal Zone may also require additional review or a Coastal Development Permit.
