Building a 2-Story ADU in East LA: Expert Insights from the Field

As housing demand continues to rise across California, many homeowners are turning to Accessory Dwelling Units (ADUs) as both a practical housing solution and a long-term investment strategy.

At Ataman Studio, we recently collaborated with Ortiz General Builders on a unique garage conversion project in East Los Angeles, transforming an outdated detached structure into a fully functional two-story ADU.

This case study offers an in-depth look at how the project was executed — from early ADU design planning and municipal approvals to construction realities, budget adjustments, and long-term rental performance — along with expert insight for homeowners considering a similar build in California.

Why ADUs Are Still a Smart Investment in 2025

Whether the goal is creating additional family living space, generating rental income, or increasing overall property value, ADUs continue to offer one of the most flexible residential investment opportunities in California.

In Los Angeles’ competitive housing market, converting underutilized structures such as garages into self-contained dwellings can produce meaningful long-term returns when approached with realistic ADU cost expectations and permit-conscious planning.

In this project, for example, the homeowner invested approximately $180,000 and stands to rent out the completed ADU for up to $2,500 per month, all while carrying only about $1,200 per month in loan payments — creating positive monthly cash flow from day one.

Project Overview: From Garage to 2-Story ADU

• Location: East Los Angeles.
• Type: Garage conversion + second-story addition.
• Size: ~800 sq ft total (garage/laundry on 1st floor + 1-bedroom ADU above).
• Timeline: Estimated 6–8 months.
• Initial Budget: $180,000.
• Final Cost (with foundation fixes): ~$192,000.
• Rental Value: $2,200–$2,500/month.
• Property Value Increase: $380,000–$400,000.

This project highlights the potential of maximizing your property’s value and rental income through smart ADU design and construction. Converting an existing garage and adding a second story can be a cost-effective way to add living space and generate passive income, especially in high-demand areas like East Los Angeles.

If you’re considering a similar project, our team at Ataman Studio specializes in garage conversions and full ADU design services tailored to California’s building codes and your specific needs.

Design & Planning: Start with Realistic Goals

Before construction begins, accurate budgeting depends on having complete architectural, structural, and permitting documentation in place.

Clients often ask, “How much does it cost to build an ADU in California?” — but without clearly defined layouts, engineering assumptions, and municipal review requirements, any estimate remains highly preliminary.

Standard one-story ADUs typically range from $250 to $300 per square foot, while two-story units often add another $50 to $75 per square foot due to deeper foundations, reinforced framing, and increased structural coordination.

💡 Pro Tip: Working with an experienced ADU design team that combines architects, structural engineers, and permitting specialists can significantly reduce redesign risk, approval delays, and mid-project budget surprises.

Foundation Surprises: What Lies Beneath

In this project, a major challenge came early on: the original garage foundation was inadequate, with a concrete slab only 2.5–3 inches thick in places. Our team had to demolish the entire base and pour a new, fully reinforced foundation. The process, including engineering revisions, city inspections, and concrete work, added ~$12,000 to the budget and took about 6 weeks.

👉 Expert Tip: Hire a contractor to perform a preliminary foundation inspection or core drilling before design is finalized. Though it adds a small upfront cost, it could save you thousands later.

The Construction Process: Step by Step

Here’s how we broke the project down:

1. Demolition & Preparation
   • Removed 99% of the original structure
   • Preserved one wall to maintain legal setbacks (critical in tight LA lots)
2. Foundation Work
   • Full rebar-reinforced slab
   • Pre-inspections to reduce risk of rework
3. Framing & Structural Build
   • Used heavy-duty 2×14 lumber for strength
   • Completed framing in-house to control costs
4. Plumbing, Electrical & Inspections
   • Installed new utility lines (~80 ft of trenching)
   • Passed rough inspections quickly thanks to updated plans
5. Interior & Finishes (in progress)
   • Standard materials to keep budget manageable
   • Option to upgrade finishes for higher-end rentals

Costs Beyond the Build: Don’t Forget Utilities

When budgeting your ADU, remember that utility hookups often add significant costs beyond the base construction price. For example, trenching and installing gas, water, and electric lines for this project—about 40 feet from the main house—cost between $30,000 and $40,000. This includes concrete cutting, inspections, and coordination with the city.

Utility expenses can vary widely depending on your property’s layout and local requirements, so planning early is key to avoiding surprises.

To better estimate your total costs, try our ADU Cost Calculator. It helps you factor in utilities and other expenses so you can plan your project with confidence.

Timeline: What to Expect

Delays usually come from:

• Unforeseen site conditions (like foundation issues).
• Slow permit processing or inspection scheduling.
• Custom material lead times.

One-Story vs Two-Story ADU: Which Is Better?

💬 Expert Take: Two-story ADUs are great for small urban lots where footprint is limited. One-story builds are cheaper and faster if you’ve got backyard space to spare.

How to Save Money When Building an ADU

Building an ADU can be a smart investment, but costs can quickly add up without careful planning. Here are key strategies to control your budget without sacrificing quality:

Stick to Standard Finishes: Choosing basic yet durable kitchens, flooring, and fixtures can save tens of thousands of dollars. Standard materials are widely available, easier to install, and often come with warranties, reducing long-term maintenance costs.

Keep the Layout Simple: Opt for an open floor plan with one bedroom and one bathroom. Simple, efficient layouts minimize framing, plumbing, and electrical complexity, which lowers labor and material expenses. Complex floor plans or multiple rooms increase costs exponentially.

Leverage Existing Structures: If possible, convert an existing garage or underutilized space into your ADU. Garage conversions avoid the need for new foundations and framing, which are among the most expensive parts of construction. This approach speeds up the project and reduces permit complexities.

Avoid Custom Elements Unless Budget Allows: Custom kitchens, unique architectural features, or high-end finishes can significantly raise costs. These are worthwhile only if your budget comfortably covers them. Otherwise, focus on standard designs that maximize function and durability.

Implementing these strategies early in the design phase can help you stay within budget and avoid costly changes during construction. For a personalized estimate and cost-saving tips tailored to your property, check out our ADU Cost Calculator.

Conclusion: Should You Build an ADU in 2025?

Absolutely. Whether you’re a homeowner looking to house family or an investor planning to generate rental income, an ADU is one of the smartest property upgrades you can make. With proper planning, the right design team, and a skilled builder, your project can be profitable, efficient, and compliant with California ADU regulations.

Note: All prices and cost estimates are provided based on 2025 data and may vary depending on project scope and location.

Ready to Start Your Own ADU Project?

Successful ADU projects rarely depend on construction alone — they depend on accurate planning, realistic budgeting, and permit-ready documentation from the beginning.

At Ataman Studio, we provide complete ADU design, ADU floor plans, engineering coordination, and ADU permits for projects ranging from garage conversions to custom-built two-story units throughout Los Angeles and surrounding California jurisdictions.

Whether you’re evaluating rental potential, lot feasibility, or total construction scope, early coordination usually determines whether an ADU project stays efficient or becomes unnecessarily expensive.

If you’re exploring a future ADU build, our team can help you approach the process with realistic numbers and California-specific planning insight.