Prefab ADU in Berkeley | Backyard Home Solutions with LiveLarge

Berkeley ADU Standards

Prefab ADU in Berkeley

What is an Accessory Dwelling Unit (ADU)?

An ADU is an independent residential unit on the same lot as a primary home, providing additional living space, rental opportunities, or multi-generational housing. A Prefab ADU is a permanent, factory-built backyard home that meets local zoning and building codes, making it ideal for long-term living.

Tiny homes, often confused with prefab ADUs, are small, mobile units built on wheels. While both can be ADUs, prefab ADUs are stationary and built to last, while tiny homes face more zoning challenges due to their mobility.

Planning to Build an ADU in Berkeley?

LiveLarge specializes in designing and building ADUs—whether prefab ADUs or modular homes—that meet local standards while optimizing your space. Our expert team will assist you every step of the way, from permits to design and construction, ensuring your ADU project is hassle-free.

Zoning and Lot Size:

ADUs are permitted in all residential zoning districts, including R-1 (Single-Family Residential), R-2 (Two-Family Residential), and R-M (Multi-Family Residential) zones, as well as in Planned Development (PD) districts (following R-1 standards). There is no minimum lot size requirement, as long as the property contains an existing dwelling unit, making it ideal for prefab ADUs.

Lot Size and Floor Area:

Junior ADU: Max 500 sq. ft.
Studio or 1-Bedroom ADU: Max 850 sq. ft.
2+ Bedroom ADU: Max 1,000 sq. ft.

ADUs converted from existing structures are not subject to size limitations unless new space is added, offering flexibility for modular homes and prefab ADUs.

Setbacks and Height:

Detached ADUs:
- One-Story Units: No setbacks required.
- Two-Story Units: Must have a minimum setback of 5 feet for new construction, with a height limit of 20 feet.
Attached ADUs: Must comply with the setbacks and zoning regulations of the existing structure, with a height limit of 25 feet, ideal for prefab ADUs or modular homes that blend seamlessly with the main house.

Design and Layout:

Kitchen: ADUs must include a full kitchen with a sink, counter space, cabinets, stove, and refrigerator.
Bathroom: A full bathroom with a sink, toilet, and shower/bathtub is required.
Storage: At least 60 sq. ft. of storage space must be provided.
Entrance: All ADUs must have a separate exterior or independent entrance.

Parking:

Junior ADUs: No parking required.
ADUs: No parking is required unless located within the Hillside Overlay, where one parking space per ADU is required, unless exemptions apply. Parking spaces must be dust-free, mud-free, and may be located in the front setback area if replacing an existing garage or parking space.

Additional Design Guidelines:

Building Separation: Detached ADUs must maintain a separation of 5-8 feet, depending on location (outside or within the Hillside Overlay).
Architectural Features: Projections like eaves and bay windows may extend up to 2 feet into required front and side setbacks, as long as a 2-foot setback from property lines is maintained.
Roof Decks: Not permitted in the Hillside Overlay area but allowed in other areas, as long as the height limit is adhered to.

Rental and Occupancy:

Rental Restrictions: ADUs and Junior ADUs cannot be rented as short-term rentals.
Owner Occupancy: The owner must live in either the primary dwelling or the Junior ADU. ADUs can be rented separately from the primary residence.

For more detailed information, visit the City of Berkeley’s official ADU page. Let LiveLarge help transform your property with a thoughtfully planned ADU. Whether you’re looking for a prefab ADU or modular home, our expertise in ADU design, pre-approved plans, and construction ensures your project meets local standards while maximizing space and functionality. Contact LiveLarge today to start building your perfect backyard home!

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