What Is A DADU? (DADU Meaning & Examples)

An illustration of a DADU (converted garage) next to a house

A Detached Accessory Dwelling Unit (DADU) is a secondary housing unit located on the same property as a primary residence. 

Unlike attached units such as basement apartments or in-law suites, DADUs are separate structures, often taking the form of small cottages, garages, or standalone tiny homes. 

These units are a type of ADU and are gaining popularity as a flexible solution to housing shortages and urban density challenges.

Examples Of DADUs

Let’s take a look at some examples of DADUs.

Standalone Cottages

Standalone cottages are independent structures that often resemble small houses. These units typically include all necessary amenities, such as a kitchen, bathroom, and living area. 

They are ideal for homeowners seeking to provide a complete and private living space for tenants or family members. 

Garage Conversions

Garage conversions transform existing detached garage spaces into livable units. 

This type of DADU is cost-effective because it utilizes the existing structure, reducing construction costs. 

Above-Garage Units

Above-garage units, also known as carriage houses, are built above an existing detached garage. 

This type of DADU maximizes vertical space and is an excellent option for properties with limited ground area.

Benefits and Uses of DADUs

DADUs provide versatile housing options that address urban density challenges and affordability issues. 

DADUs serve various other purposes for homeowners as well, not only for financial benefits but also as extra space family space.

Rental Income 

Homeowners can lease DADUs to generate additional income. 

This can be particularly beneficial in high-cost living areas, where rental income can help offset mortgage payments and property taxes.

Multigenerational Living 

Families can use DADUs to accommodate aging parents or adult children, promoting close-knit family structures and providing an affordable housing solution within the family unit.

Flexible Space

DADUs can function as home offices, guest houses, or creative studios, providing valuable space without expanding the primary residence. 

This flexibility makes them attractive for homeowners looking to maximize their property’s potential.

Legal and Zoning Considerations

Implementing DADUs requires adherence to local zoning laws and building codes. 

Cities like Seattle and Portland have revised zoning regulations to facilitate DADU construction, significantly increasing permit applications and completed units.

Some key considerations include:

  • Property Size: Minimum lot size requirements vary by municipality, ensuring that DADUs do not overwhelm the neighborhood’s infrastructure.
  • Design Standards: DADUs must comply with design guidelines to maintain neighborhood aesthetics, including height restrictions, setback requirements, and architectural style considerations.
  • Parking Requirements: Some areas mandate additional parking spaces for DADU occupants to mitigate potential street parking congestion.

Economic and Social Impact

The economic benefits of DADUs extend beyond individual homeowners, and studies have shown that ADUs (DADUs included) contribute to local economies.

Additionally, the presence of DADUs can lead to more vibrant and diverse communities, offering affordable housing options that help mitigate housing crises in high-demand areas.

Challenges and Solutions

While DADUs offer many advantages, they also present challenges:

Cost of Construction

Building a DADU can be expensive, with costs varying depending on size, design (Presite can help with this one), and local construction rates. 

However, financial incentives such as grants and low-interest loans are available in some regions to support homeowners in undertaking these projects.

Community Resistance

Some neighborhoods oppose DADUs due to concerns about increased density and changing community dynamics. 

Effective community engagement and education can address these concerns by highlighting the benefits of DADUs, such as providing affordable housing and supporting multigenerational living arrangements.

Environmental Benefits

DADUs also offer environmental advantages. 

Smaller living spaces typically require fewer resources to build and maintain, resulting in a lower carbon footprint.

They also allow people to live closer to work, which also contributes positively to the environment.

Success Stories & Challenges

Several cities have successfully integrated DADUs into their housing strategies:

  • Portland, Oregon: Portland has been a pioneer in promoting DADUs (see study) with a streamlined permitting process and financial incentives for homeowners. As a result, the city has seen a substantial increase in DADU construction, contributing to its housing stock and providing affordable rental options.
  • Vancouver, Canada: Vancouver has implemented policies to encourage the development of DADUs, although challenges still remain. These units have helped address the city’s housing shortage and provide more diverse housing options in established neighborhoods.

The future of DADUs is clear-cut, but challenges still remain with legislation.


DADUs, or Detached Accessory Dwelling Units, are independent housing units on the same property as a primary residence. 

They offer diverse benefits, including rental income, flexible living space, and solutions to housing affordability. 

By understanding and addressing legal, economic, and social considerations, cities can effectively integrate DADUs into their housing strategies, promoting sustainable urban development.

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