Detached Accessory Dwelling Unit Overlay

WHAT IS THIS OVERLAY?  The Detached Accessory Dwelling Unit (DADU) Overlay would provide a tool for RS zoned neighborhoods that want to increase diversity in their housing stock without allowing duplexes.  Adopting a DADU overlay would enable properties within the overlay to add a subservient home in the back of the principal home for long-term rental.

WHY DO WE NEED IT?  Many neighborhoods have downzoned to RS to prevent the replacement of existing single-family homes with two-family structures, often in the form of “tall skinnies”,  increasing density, exacerbating stormwater run-off problems, and driving up home prices.  As modest size homes have been replaced with very large duplexes, the options for housing for single adults and retirees have been reduced.

WHERE WOULD IT APPLY? A DADU overlay would apply only in neighborhoods that choose to go through the legislative process to adopt it.  The proposed overlay rules specify that a minimum of 30 contiguous lots is required with boundaries defined by physical separations like streets, alleys, or railroad tracks.  This ensures that the overlay adoption would be resident-driven.

WHAT ARE THE GUIDELINES? Section 17.16.030 of the Metro Code already spells out detailed requirements for the size, location, and style of DADUs.  The DADU must have a maximum of 700 square foot living space and a footprint maximum of either 750 or 1000 square foot depending on the lot size.  Height must be less than the principal structure. The DADU must be behind the principal structure with minimum setbacks of three to ten feet.  The DADU must be of similar style, design, and material color as the principal structure and must use similar architectural characteristics, including roof form and pitch.

HOW WOULD IT WORK?  A neighborhood interested in applying for a DADU overlay would work with their Council Member to determine the appropriate boundaries and file an ordinance.  This would require notification to every household in the proposed overlay, community meetings, Planning Commission and Metro Council public hearings, and three readings before the Metro Council.  Once a DADU overlay has been adopted, properties within the overlay would be entitled to build a secondary home within the specific guidelines already spelled out in the Metro Code.

HOW CAN I SUPPORT THIS? Comments and letters of support can be sent to the Planning Commissioners at [email protected] by February 23 before their Public Hearing and to Council Members by March 1 at https://www.nashville.gov/Metro-Council/Contact-Council-Members.aspx or tune into the Council public hearing on March 2 at 6:30.