ADU vs DADU: What’s the Difference
— and Which One Is Right for You?
— and Which One Is Right for You?
In Seattle, more and more homeowners are putting their unused space to good use by building an ADU or DADU.
This isn’t just a trend — it’s a smart way to increase your property value, generate rental income, or create private space for family.
This isn’t just a trend — it’s a smart way to increase your property value, generate rental income, or create private space for family.
But what exactly are ADUs and DADUs — and how do they differ?
What is an ADU?
An ADU (Accessory Dwelling Unit) is a secondary living space either attached to your main home or located somewhere on your lot.
It can serve as:
- A private apartment for family
- A rental unit
- A home office or creative studio
- Attached ADU— an addition connected to the main home (e.g. over a garage or side extension)
- Basement ADU— a converted basement
- Garage Conversion— a remodeled attached garage
What is a DADU?
A DADU (Detached Accessory Dwelling Unit) is a completely separate structure built on the same lot as your main home.
It’s often called a“backyard cottage,” “lane house,” or “tiny home.”
A DADU is a fully independent residence — with its own entrance, kitchen, bathroom, and utilities.
At Modern Buildings, DADUs are our specialty.
Why Are So Many Homeowners Choosing DADUs?
In Seattle and surrounding areas where land is expensive, building a DADU means creating a second home without buying a new lot.
You can:
You can:
- Rent it out legally (when compliant with local rules)
- Use it as a guesthouse or for aging parents
- Increase your home's resale value and marketability
Which One Should You Choose — ADU or DADU?
Choose an ADU if:
- You’re on a tighter budget
- You need a faster solution
- You don’t plan on long-term rentals
Choose a DADU if:
- Privacy is a priority
- You’re thinking about long-term rental income or ROI
- Your lot can accommodate a detached structure
Need Help Getting Started?
At Modern Buildings, we specialize in full-service DADU construction in Seattle and the greater King County area.
We handle everything: architectural plans, permits, construction, utility hookups, and finishing.
Contact us for a free consultation — we’ll evaluate your lot, walk you through what’s possible, and show you real numbers on rental income and timelines.
At Modern Buildings, we specialize in full-service DADU construction in Seattle and the greater King County area.
We handle everything: architectural plans, permits, construction, utility hookups, and finishing.
Contact us for a free consultation — we’ll evaluate your lot, walk you through what’s possible, and show you real numbers on rental income and timelines.