What is the Difference Between an ADU vs DADU?


In recent years, the need for more living space has surged exponentially. Seattle homeowners are increasingly exploring innovative solutions to maximize their property’s potential. Accessory Dwelling Units (ADUs) and Detached Accessory Dwelling Units (DADUs) have become popular options thanks to their versatility and the added value they bring to properties. In this blog post, we’ll delve into the definitions of ADUs and DADUs, highlighting their differences and similarities. Plus, our team of design build experts will provide insights into their growing presence in Seattle. Whether you're considering expanding your home or looking for a new investment opportunity, we’re here to help you understand the nuances between the two.


Defining ADU (Accessory Dwelling Unit)

What Is an ADU?

An Accessory Dwelling Unit, commonly referred to as an ADU, is a secondary housing unit on a single-family residential lot. ADUs are typically attached to or part of the primary residence. They are usually smaller in size and can be located in the basement, attic, or even as an addition to the main house.

Common Uses and Benefits of ADUs

ADUs can serve many different purposes, from providing additional living space for family members to generating rental income. They are also ideal for creating a home office, guest suite, or independent living quarters for aging parents. The benefits of ADUs include increased property value, flexible living arrangements, and the potential for passive income.


Defining ADU (Accessory Dwelling Unit)

What Is a DADU?

A Detached Accessory Dwelling Unit (DADU), also known as a backyard cottage or carriage house, is a stand-alone structure separate from the primary residence. Unlike ADUs, DADUs are not attached to the main house but share the same property lot.

DADUs are independent buildings, often located in the backyard or other areas of the property. They provide complete living facilities, including a kitchen, bathroom, and sleeping area, offering a fully functional, self-contained living space.

Unique Features and Advantages of DADUs

One of the primary benefits of DADUs is the privacy they offer. Because they are detached from the main house, they provide a  fully separate living environment ideal for tenants, extended family members or even as a home office or studio. DADUs also enhance the property’s versatility and can significantly boost its market value.

Key Differences Between ADUs and DADUs

Now let’s break down some of the key differentiating points of each type of structure. When comparing ADUs and DADUs, several key differences are apparent, such as:

  • Location: ADUs are attached to or part of the main house, while DADUs are completely separate structures.
  • Privacy: DADUs offer more privacy due to their standalone nature.
  • Design Flexibility: DADUs allow for more creative and varied design options since they are independent structures.

Commonalities Between ADUs and DADUs

Purpose of Increasing Housing Options

Both ADUs and DADUs address the need for more flexible and diverse housing solutions, providing additional living space on existing residential properties. This point is especially crucial in densely populated areas, like Seattle.

Rental Income Potential

Both types of units can generate rental income, making them attractive investments for homeowners looking to maximize their property’s earning potential.

Additional Space for Visitors and Guests

ADUs and DADUs provide comfortable accommodations for guests, offering privacy and independence while staying close to the main residence.

Additional Space for Your Own Family

These units are excellent for multigenerational living, offering a solution for families needing extra space for aging parents, adult children or other relatives.


ADUs and DADUs in Seattle

Regulations and Guidelines in Seattle

Seattle has specific regulations governing the construction and use of ADUs and DADUs. In order to be in compliance, homeowners must adhere to zoning laws, size restrictions and occupancy limits. It's essential to understand these guidelines to ensure your project meets all legal requirements. Here at CRD Design Build, we excel at navigating the complexities of these regulations and are more than happy to help work with you on your own project!

Examples of ADU and DADU Projects in Seattle

CRD has completed numerous ADU and DADU projects in Seattle, transforming properties into more functional and valuable spaces. These projects showcase the potential and versatility of these units, tailored to meet the unique needs of Seattle homeowners. Here are a few recent examples:

Greenwood DADU Conversion



Freemont ADU



In summary, while ADUs and DADUs offer similar benefits, such as increased living space and rental income potential, they differ in structure and privacy. Simply put, ADUs are attached to the main house, whereas DADUs are standalone units.

If you’re considering adding an ADU or DADU to your Seattle property, CRD Design Build is here to help. Our team of experts can guide you through the process, ensuring your project meets all regulations and fulfills your vision. Contact us today to explore the possibilities and enhance your home with an ADU or DADU.

Article Categories: Interior Design, Accessory Dwelling Units, Design Tips And Trends, Universal Design, Backyard Cottages And Adus

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