Two-Story ADU in Los Angeles - Rules, Costs, and Design Options

Building a two-story accessory dwelling unit (ADU) in Los Angeles is one of the smartest ways to maximize livable space on a smaller lot.

By stacking square footage vertically, you get a full-sized home without sacrificing your entire backyard. Since California passed SB 897 in 2022, two-story ADUs have become easier to build across the state, and Los Angeles homeowners are taking advantage.

This guide will provide you with everything you need to know about the rules, costs, and design options for a two-story ADU in LA.

When you're ready to start planning your accessory dwelling unit, LADU can handle the entire process for you.

We specialize in building ADUs in Los Angeles and have developed a streamlined approach that removes the stress associated with designing, permits, and construction. Schedule your free site visit today, or call (213) 855-3334 to learn more about our services.

California Height Limits for Two-Story ADUs

State law sets the height limits that determine whether you can build a two-story ADU on your property. These limits were significantly expanded by SB 897 and AB 2221 in 2022 and are now codified in California Government Code sections 66310-66342.

The height allowances depend on your property type and ADU configuration:

Two-Story Detached ADU on a Single-Family Lot

The base height limit for a detached ADU with 4-foot side and rear setbacks is 16 feet. At this height, a two-story design is tight but possible with careful planning, especially for smaller units.

The state also allows an additional 2 feet of height for roof pitch so that the ADU roofline can align with the primary dwelling.

Two-Story Detached ADU on a Multifamily Lot

If your lot has an existing or proposed multifamily, multistory dwelling, the height limit increases to 18 feet.

If the ADU includes two or more bedrooms and the primary dwelling is two or more stories, the limit rises to 20 feet. These allowances make two-story construction much more practical.

Two-Story Attached ADU

An attached ADU can reach up to 25 feet in height or the height of the existing primary dwelling, whichever is lower. This makes attached two-story ADUs the most flexible option for homeowners who want maximum square footage.

Above-Garage ADU: The Popular 2-Story ADU Option

One of the most common two-story ADU configurations in Los Angeles is the above-garage ADU, sometimes called a carriage house. This design places living space on a second story above an existing or newly built garage, preserving both parking and yard space.

Above-garage ADUs are especially popular in neighborhoods where lot coverage is limited. The garage occupies the ground-level footprint, and the ADU sits on top. This approach works well for both detached garages in the backyard and attached garages at the front of the property.

Key considerations for above-garage ADUs:

• Structural reinforcement of the garage may be needed to support a second story
• Stairway access must be planned into the design (exterior stairs are common)
• The combined structure must comply with height limits for your lot type
• Fire-safety setbacks apply in Very High Fire Hazard Severity Zones (VHFHSZ)
• LADBS pre-approved standard plans include above-garage two-story designs

How Much Does a Two-Story ADU Cost in Los Angeles?

Two-story ADUs in Los Angeles generally cost more per square foot than single-story units because of the added structural complexity. Here are current cost ranges based on LA market data:

• Construction cost per square foot: $300 to $400+ for new construction. Two-story units tend toward the higher end of this range due to structural engineering, deeper foundations, and more complex framing.
• Total project cost for a two-story ADU: $350,000 to $400,000+, depending on size, finishes, and site conditions.

Additional cost factors:

• Building plans and architectural design: $8,000 to $20,000
• City plan check, ADU permit, and fees: $5,000 to $20,000
• Structural engineering (required for two-story): $3,000 to $8,000
• Foundation work (deeper footings for two-story): Adds $5,000 to $15,000 vs. single-story
• Utility connections (electrical, water, sewer, gas): Varies by distance from mains
• Landscaping, hardscape, and fencing: Additional cost beyond the structure itself

While the per-square-foot cost is higher, two-story ADUs use significantly less land. A 1,000 sq. ft. two-story ADU needs only a 500 sq. ft. footprint compared to 1,000 sq. ft. for a single-story. For properties where yard space is at a premium, the trade-off often makes financial sense.

To see a full breakdown, read our guide on how much it costs to build an ADU in Los Angeles.

Two-Story ADU Plans and Design Options

Two-story ADUs offer more design flexibility than their single-story counterparts. Common ADU floor plans and layout approaches include:

• Bedrooms upstairs, living space downstairs: The most popular configuration. The ground floor holds the kitchen, living room, and bathroom, while one to three bedrooms occupy the second floor. This layout provides natural separation between public and private spaces.
• Studio-over-garage: A single open-plan studio on the second floor above a garage. Best for rental income or guest housing. Typically 400 to 600 sq. ft. of living space.
• Two-bedroom with flex space: A two-bedroom ADU with a ground-floor room that can serve as a home office, den, or third bedroom. Popular with multigenerational families.
• Full two-bedroom/two-bathroom: Maximizes the 1,200 sq. ft. allowance with two full bedrooms, two bathrooms, a kitchen, and separate living and dining areas. This configuration commands the highest rental rates.

Privacy matters in two-story design. Window placement on the second floor should account for neighbor sightlines. Frosted glass, clerestory windows, and strategic orientation can maintain privacy without sacrificing natural light.

Setback and Zoning Requirements

Two-story ADUs must comply with setback requirements outlined in state law and local zoning.

Key setback rules for Los Angeles:

• 4-foot minimum side and rear yard setbacks for new detached ADUs (state law)
• Front yard setbacks follow local zoning requirements
• Existing structures converted to ADUs do not require additional setbacks
• Properties in VHFHSZ may have additional fire-safety setback requirements

The permit process for ADUs in Los Angeles is ministerial, meaning your application is approved as long as it meets objective development standards. There is no discretionary review or public hearing required.

ADU construction must also comply with Title 24 energy efficiency standards, which include insulation, window performance, and HVAC requirements. Two-story units have more exterior wall area, which can slightly increase the cost of meeting these standards.

Pre-Approved Plans and Prefab Options

LADBS offers a Standard Plan Program with pre-approved two-story ADU design options, including two-story configurations. Using a pre-approved plan can significantly reduce your permitting timeline since the design has already been reviewed and accepted.

Prefabricated two-story ADU options are also available from several manufacturers. Prefab ADUs are built in a factory and assembled on-site, which can reduce construction time by several months. However, site preparation, foundation work, and utility connections still apply.

The California Department of Housing and Community Development (HCD) publishes an ADU Handbook (updated March 2026) that serves as the authoritative reference for statewide ADU regulations, including height limits and development standards.

Rental Income From a Two-Story ADU

Larger two-story ADUs with two or more bedrooms command the highest rental rates in Los Angeles. Current market rates for well-finished two-bedroom ADUs range from $2,500 to $3,500+ per month, depending on location and amenities.

A two-story ADU is one of the best long-term investments a Los Angeles homeowner can make. The combination of rental income, property value increase, and flexible use (family housing, home office, or guest suite) makes it a versatile addition to any property.

Is a Two-Story ADU the Right Move for Your Property?

A two-story ADU isn't just a space-saving solution; it's a strategic way to unlock the full potential of your property.

If your lot is constrained, your long-term plans include rental income, or you want to create flexible living space for family, building vertically gives you options that a single-story unit simply can't match.

Early design decisions impact everything that follows. The difference between a "good" ADU and a highly functional, high-performing one often comes down to planning, not just square footage.

That's where working with an experienced, full-service ADU builder becomes critical. Instead of navigating zoning rules, engineering challenges, and contractor coordination on your own, you can move forward with a clear, streamlined plan from day one.

If you're considering a two-story ADU in Los Angeles, LADU can guide you through every step, from feasibility and design to permits and construction arrangements. Schedule your free site visit or call (213) 855-3334 to see what's possible on your property.

Frequently Asked Questions About Building a Two-Story Accessory Dwelling Unit

Can you build a two-story ADU in Los Angeles?

Yes. California state law allows two-story ADUs subject to height limits that range from 16 to 25 feet depending on the ADU type (detached vs. attached) and lot characteristics. SB 897, passed in 2022, expanded these height allowances significantly.

How tall can a two-story ADU be in California?

Detached ADUs can be 16 to 20 feet tall depending on lot type, plus an additional 2 feet for roof pitch. Attached ADUs can reach up to 25 feet or the height of the primary dwelling, whichever is lower.

Is a two-story ADU more expensive than a single-story?

Yes. Two-story ADUs cost more per square foot due to structural engineering, deeper foundations, and more complex framing. However, they use less land, which can be a significant advantage on smaller lots.

Do I need special permits for a two-story ADU?

No special permits are required beyond the standard ADU permit from LADBS. The process is ministerial as long as your design meets height, setback, and size standards. Using a pre-approved plan from LADBS can speed up the process.

Can I build a two-story ADU above my garage?

Yes. Above-garage (carriage house) ADUs are one of the most popular two-story configurations in LA. The existing garage may need structural reinforcement, and the combined structure must meet applicable height limits.