The main difference between ADUs (Accessory Dwelling Units) and DADUs (Detached Accessory Dwelling Units) are that ADU’s are generally attached structures, where as DADUs are detached from the home.
Understanding the core differences between an ADU and a DADU can help you decide which solution works best for your lifestyle, property, and long-term goals.
What Is an ADU?
An Accessory Dwelling Unit (ADU) is a secondary housing structure located on the same lot as a primary residence. Unlike a traditional home addition, an ADU is a fully independent living space with its own kitchen, bathroom, and sleeping quarters.
ADUs can be built in several formats:
- Interior conversions (like a finished basement or attic)
- Attached units (extensions connected to the main house)
- Garage conversions (renovating an existing garage into a livable space)
They are often used to house extended family, serve as rental units, or provide a flexible guest space.
What Is a DADU?
A Detached Accessory Dwelling Unit (DADU), sometimes referred to as a backyard cottage or carriage house, is a standalone structure built separately from the main residence on the same lot.
DADUs function just like ADUs—they include a kitchen, bathroom, living space, and sleeping quarters—but they are not physically connected to the main house. Because of this, they offer greater privacy and can often be customized more extensively in terms of layout and design.
Common uses for DADUs include:
- Independent rental properties
- Housing for aging parents or adult children
- Private home offices or creative studios
- Short-term rental units (where permitted)
Key Differences Between ADUs and DADUs
| Category | ADU (Accessory Dwelling Unit) | DADU (Detached Accessory Dwelling Unit) |
| Structure and Placement | Integrated into or attached to the main house. Often designed as basement apartments, attic suites, or home extensions. | Separate, stand-alone buildings typically located in the backyard or elsewhere on the same property. |
| Privacy | Shares walls, entrances, or utilities with the main house. Less privacy—ideal for family or guests. | Completely separate structure. Offers more privacy and independence—better for tenants or relatives. |
| Cost | More cost-effective, especially when converting existing spaces. Lower construction costs due to shared resources. | Higher cost due to standalone construction, new utilities, and permit requirements. Potentially higher ROI. |
| Design Flexibility | Limited by the existing structure’s layout and footprint. Renovation may be restricted by architecture. | Greater freedom in design and layout. Can be built from scratch to suit specific needs. |
| Rental Income Potential | Ideal for generating modest rental income or hosting short-term guests. | Can command higher rent due to size, privacy, and appeal to renters seeking independent living |
Benefits of Adding an ADU or DADU
Whether attached or detached, both ADUs and DADUs offer a range of advantages for homeowners:
- Boost Property Value: Homes with secondary units often appraise higher, especially in competitive housing markets.
- Multi-Generational Living: Great for keeping family close while maintaining separate living quarters.
- Rental Opportunities: Whether you rent long-term or short-term, these units provide potential for extra income.
- Flexible Usage: These units can evolve with your needs—use them as a home office today and a guest house tomorrow.
- Aging in Place: Allow older family members to live independently nearby with safety and comfort.
Considerations Before Building
Before moving forward with an ADU or DADU, there are important factors to keep in mind:
Local Zoning Laws
Zoning and land use regulations vary by city and municipality. Some areas limit the number of units allowed on a lot, require parking space, or enforce setback rules that may affect DADU placement.
Permitting Process
Both types of structures typically require building permits. You’ll need to work with your local planning department to ensure your project complies with code requirements.
Budget and Financing
Construction costs can range significantly based on the type of unit, finishes, labor costs, and whether it’s a new build or renovation. Set a realistic budget, and explore financing options such as home equity loans or renovation loans.
Lot Size and Layout
Not every property is suitable for a DADU. Assess your lot’s size, existing structures, and available space to determine what’s possible.
Conclusion
Choosing between an ADU and a DADU depends on your goals, available space, and budget. If you’re looking for a more affordable, quicker solution and don’t mind being connected to the main house, an ADU might be the right choice. If privacy, flexibility, and long-term investment are top priorities, a DADU could be worth the higher upfront cost. If you’re ready to explore the possibilities of expanding your living space or increasing your property’s value with an ADU or DADU, the experts at Stonehearth Remodeling can help. With experience navigating zoning laws and designing custom solutions, we’re here to bring your vision to life—right in your own backyard.
