Building an Accessory Dwelling Unit (ADU) in Utah offers homeowners a flexible way to add extra living space, whether for family members, renters, or guests. On average, homeowners can expect to spend anywhere from $150,000 to $400,000 or more. However, ADU costs in Utah can vary widely.
How Much Does an ADU Cost To Build?
Whether you’re looking to attach an ADU to your home, convert an existing space, or build a separate structure, each option comes with its own set of cost considerations. Here’s a breakdown of the average costs for different types of ADUs in Utah.
Attached ADUs
An attached ADU isn’t your average home addition. It’s a new, separate living space that is built directly onto the main home, typically sharing a wall.
The average cost to build an attached ADU in Utah can range from $150,000 to $250,000. Because attached units often require fewer structural changes and share utilities with the main home, they are generally less expensive than detached options.
Detached ADUs

A detached ADU stands alone on the property and is often built from the ground up. These units offer more privacy and independence for tenants or family members. Due to the need for a foundation, separate utilities, and more extensive construction, detached ADUs in Utah can cost between $200,000 and $400,000 or more, depending on size and design complexity.
Conversions (Garage, Basement, or Attic)
Converting an existing space, like a basement, attic, or garage, into an ADU is one of the most cost-effective options. Since the main structure is already in place, these projects typically cost between $150,000 and $225,000 in Utah. However, the final cost will depend on the level of renovation required to make the space suitable for living.
What Factors Contribute to the Total Cost of an ADU?
The cost to build an ADU can vary significantly due to the flexibility in design and the numerous types of ADUs available. Here are the key factors that influence the total cost:
- Design and Layout: Custom floor plans, unique designs, and high-end layouts can significantly increase costs.
- Materials and Finishes: Premium finishes, such as high-end flooring or energy-efficient windows, will raise the overall price of your ADU.
- Permits and Fees: Local regulations in Utah require permits for building ADUs, and fees can vary based on location and scope of the project.
- Labor and Contractor Rates: Skilled labor can come at a premium, especially in high-demand areas of Utah. Hiring experienced contractors may cost more, but it ensures the job is done right.
By considering these factors, you can better understand what affects the total cost of building an ADU. This will help you plan and budget more effectively.
How Steve Austin Homes Can Help You Plan for ADU Costs

With years of experience building accessory dwelling units in Utah, Steve Austin Homes can help you navigate the budgeting process with clear, transparent ADU cost estimates. This ensures you understand the full scope of your project, avoid unexpected expenses, and stay on track with both your functional and financial goals.
As an experienced ADU contractor, we use our expertise to help you prioritize valuable upgrades without overspending, making sure your ADU project meets your needs while staying within budget. Ready to get started? Contact Steve Austin Homes today and take the next step in building your ideal ADU.
