Detached Accessory Dwelling Units, better known as DADUs, are becoming a key part of Nashville’s housing. And at the center of this is something called the DADU overlay. Understanding how a DADU overlay works can help you figure out whether your lot qualifies, what’s realistically possible, and how to move forward without getting lost in zoning jargon.
Keep reading to learn more if you’re considering a DADU in Nashville.
What Is a DADU and How Does the Overlay Fit In?
A DADU (Detached Accessory Dwelling Unit) is a small, standalone home built on the same lot as a primary single-family home. It usually includes its own bedroom or sleeping area, bathroom, kitchen, and living space—essentially a tiny, self-contained house in your backyard.
Metro Nashville Codes defines DADUs as secondary dwellings that share a lot with an existing single-family home. They’re not duplexes and can’t be sold off as separate lots. Instead, they function as:
- A long-term rental
- A space for aging parents or adult children
- A home office or studio
- A guest suite for visiting friends and family
A DADU overlay is a zoning tool that tells you where these units are allowed. The overlay modifies the base zoning in certain areas so that property owners within that overlay can legally build a DADU if they meet Metro’s requirements.
Understanding DADU in Nashville
Nashville’s DADU overlay exists to gently increase housing options in single-family neighborhoods without completely changing their character. Instead of allowing duplexes everywhere, the DADU overlay gives eligible properties the right to add a smaller, secondary home behind the main house.
A few key points about how the overlay works:
- It’s map-based. A DADU overlay is applied to a defined geographic area on the city’s official zoning map. If your property is inside that overlay, you may be eligible to build a DADU, subject to all the other rules.
- It layers on top of existing zoning. The overlay doesn’t replace your base zoning (R, RS, etc.). Instead, it adds the option of a DADU in Nashville where otherwise it might not be permitted.
- It’s meant for long-term housing. Under recent code changes, short-term rentals (STRs) are not a permitted use in newly established DADUs within these overlays. The goal is stable, long-term housing; not vacation rentals.
The DADU overlay is the green light that opens the door to building a DADU in Nashville, but you still have to meet size, placement, and design rules.
Does Your Property Qualify for a DADU in Nashville?
This is where most homeowners have questions. Whether your lot qualifies for a DADU in Nashville depends on a combination of zoning, overlays, and basic lot characteristics. At a high level, Metro’s rules look at:
- Base Zoning: Properties in certain residential districts (such as R, RS, and related categories) may be eligible if other criteria are met.
- Overlays: Your lot may need to be in a DADU overlay district, a Historic Overlay, an Urban Design Overlay, or meet specific lot size requirements for DADUs to be allowed.
- Lot Size & Coverage: Accessory structures, including DADUs, must stay under maximum square footage limits relative to the main house and overall lot size. For smaller lots under 40,000 square feet, Metro limits how large the accessory structure can be.
- Existing Structures: A DADU is only allowed on a parcel with one single-family dwelling. If your lot already has two single-family homes, you generally can’t add a DADU, even if you meet other rules.
Because zoning and overlays can be confusing, many homeowners choose to work with a local builder or design-build team that can pre-screen the lot, confirm eligibility, and flag any need for variances early on.
Steps to Getting a DADU Approved and Built
If you’re thinking seriously about a DADU overlay and what it could mean for your property, here’s what the typical process looks like:
1. Research Your Zoning and Overlays
Start by checking your property’s zoning and any overlays in place. You can use Metro’s online zoning map or talk with Metro Codes and Planning.
2. Confirm DADU Eligibility
Look at lot size, existing structures, and whether your area has a DADU overlay or other qualifying overlays (like Historic or Urban Design). If you’re working with a contractor, they can often handle this pre-screening step for you.
3. Develop a Concept and Budget
How will you use the DADU? Who will live there? Your answers drive square footage, layout, finishes, and cost. Nashville homeowners often balance rental-income potential with comfort for future family use.
4. Create Plans and Apply for Permits
You’ll need professionally prepared plans that comply with building codes, setbacks, height limits, and floor area controls. These plans are submitted to Metro Codes for permit review.
5. Build, Inspect, and Move In
Once permits are approved, construction begins. Your builder coordinates inspections at key stages—foundation, framing, utilities, and final sign-off—before anyone can occupy the DADU.
How Deed Brothers Helps Homeowners Navigate DADU Overlay
Deed Brothers, LLC is a full-service construction company based in Nashville, handling everything from land acquisition and plan selection to design, finishes, and full builds. Our work ranges from custom homes and remodeling to exterior structures like detached garages, barns, and, increasingly, DADUs.
When it comes to DADU projects, Deed Brothers can:
- Pre-screen your lot to evaluate zoning, overlays, and likely eligibility for a DADU
- Coordinate with Metro Codes to ensure your design aligns with the latest regulations
- Design and build your DADU to feel cohesive with your main home, not like an afterthought
- Help you balance budget and long-term goals, whether you’re housing family, planning for aging in place, or creating a long-term rental
If you’re ready to explore what a DADU overlay could mean for your property, reach out to us at Deed Brothers to start the conversation.