680 sq ft
2 Bed
2 Bath
Two Story ADU Plans – Maximize Space with Smart, Stylish Designs
Building a two story ADU is one of the most efficient ways to add square footage and value to your property — especially when lot space is limited. Unlike a single story layout, two level ADU designs allow you to build upward instead of outward, preserving backyard space for outdoor living, parking, or landscaping.
At Ataman Studio, we create custom 2 story ADU floor plans that comply with California’s ADU regulations and fit seamlessly with your main house and neighborhood. Whether you are looking for a modern rental unit, a private guesthouse, or a multigenerational living solution, our designs focus on function, aesthetics, and long-term value.
Why Choose a Two Story ADU?
A two story ADU plan is ideal for homeowners who want to maximize livable space without consuming too much of their lot area. Some of the most common reasons clients choose this option include:
- Space Efficiency: Double the interior square footage while keeping the footprint small — perfect for narrow lots.
- Privacy: Bedrooms can be located upstairs, with living spaces and kitchens downstairs, creating clear separation between public and private areas.
- Views & Natural Light: An elevated second floor captures better light and potential views, which is a major advantage in scenic areas.
- Rental Potential: A well-designed 2-story ADU can function like a small house, commanding higher rental rates.
Two story ADUs are particularly popular in Los Angeles, San Diego, and Bay Area neighborhoods where land prices are high, making vertical construction a smart investment.
Design & Layout Options
When designing a two story ADU, it’s important to consider circulation, privacy, and structural requirements. Here are some popular configurations we often recommend:
- Ground Floor Living, Upstairs Bedrooms – A classic layout that keeps entertaining spaces open and bright while creating a quiet retreat upstairs.
- Two Separate Units (Duplex ADU) – In some cases, a two-story ADU can function as two independent units, maximizing rental income.
- Garage + ADU Above – A common solution for small lots: keep the garage or storage at ground level and place a one-bedroom or two-bedroom ADU upstairs.
- Reverse Layouts – For properties with scenic views, we can place living spaces upstairs and bedrooms downstairs to take advantage of vistas.
Our team also focuses on stair design, ensuring it is space-efficient and meets all safety and accessibility codes.
Our Two Story ADU Design & Permit Process
Designing a 2-story ADU requires careful planning and technical expertise due to added structural complexity, fire code considerations, and height limits. Here is how we streamline the process:
- Site Evaluation & Code Research
We start with a property review and research your city’s ADU regulations — including maximum height, setbacks, parking requirements, and fire-rated wall requirements for multi-level construction. - Concept Design & Layout Options
We prepare multiple two story ADU floor plan concepts so you can visualize the best use of your space. - 3D Models & Virtual Walkthroughs
Before construction, we present 3D visualizations, allowing you to “walk through” the design and adjust features like window placement, ceiling height, and exterior style. - Engineering & Structural Plans
Because a two-story structure carries more load, we provide detailed structural drawings to ensure safety, seismic compliance, and city approval. - Permit Submittal & Approvals
Our permitting specialists compile the complete set of plans and submit them to your city’s planning department, following up to resolve comments quickly and keep your project moving forward. - Construction Support
We stay involved throughout the build, helping your contractor interpret plans and ensuring the project meets design intent.
Architectural Styles for Two Story ADUs
Your two level ADU doesn’t need to look like an afterthought. At Ataman Studio, we design units that complement your main home and neighborhood. Popular styles include:
- Modern Contemporary: Clean lines, large windows, and open-concept interiors.
- Mediterranean or Spanish Revival: Perfect for California neighborhoods with a historic character.
- Craftsman or Cottage Style: Cozy yet elegant, blending with traditional single-family homes.
- Minimalist Urban Designs: Ideal for rentals or compact city lots, maximizing function in a sleek package.
Costs & Timelines for 2-Story ADUs
Building a two story ADU generally costs more than a single story due to additional framing, structural engineering, and staircase construction. However, the cost per square foot can actually be lower because you’re building more area on the same foundation.
- Design & Permitting: Typically 3–6 months depending on city response times.
- Construction: 6–10 months depending on size and finish level.
- Costs: On average $350–$600+ per sq ft, with detached 2-story ADUs often ranging from $300,000 to $500,000 depending on complexity.
Many homeowners find the investment worthwhile as a two-story ADU can generate higher rental income and significantly increase property value.
FAQ: Two Story ADU Plans
Are two-story ADUs allowed in California?
Yes — but it depends on your city’s zoning rules. Most California jurisdictions allow two-story ADUs if you meet height restrictions (usually up to 16–18 ft for detached ADUs by right, and more with discretionary review or if your lot qualifies for SB 9 or local density bonus programs). Our team always conducts a zoning and setback analysis before designing to ensure your plan is 100% compliant.
How tall can a two-story ADU be?
Height limits typically range from 16 to 25 feet, depending on whether the ADU is attached or detached, and your city’s code. In areas like Los Angeles, detached ADUs can often go up to 20–25 feet with design review, allowing for a full two-story unit. We also consider roof styles (pitched vs. flat) to stay within height limits without compromising headroom.
Do two-story ADUs cost more than single-story ADUs?
Yes, two-story ADUs generally cost 15–25% more per square foot because of structural engineering requirements, stairs, and potentially deeper foundations. However, they allow you to maximize living space on smaller lots without sacrificing your yard — which can significantly increase property value.
Can I build a garage with a second-story ADU on top?
Absolutely. This is one of the most popular ways to add a two-story ADU on small lots. We design garage + ADU combinations that meet parking replacement requirements (if any), and we reinforce the structure to safely support the living space above.
What layouts work best for two-story ADUs?
Popular options include:
- Living area + kitchen on the first floor, bedrooms upstairs (best for privacy).
- Rental suite upstairs, home office or gym downstairs.
- Studio apartment over garage with storage or parking below.
We customize the layout based on your lifestyle and whether you plan to rent it out.
How long does it take to design and permit a two-story ADU?
Expect 4–8 months for design, structural engineering, and permitting — depending on your city’s review process. Construction can take 8–14 months, since two-story builds require additional inspections and structural work.
Start Your Two Story ADU Project
If you’re ready to maximize your property’s potential with a two story ADU, Ataman Studio can guide you through every step — from initial design concepts to final city approval. Our experience with complex ADU projects ensures that your new space will be both code-compliant and beautiful.