Franklin, TN Accessory Structures: ADU Rules (2026)

The Franklin Zoning Ordinance defines an Accessory Dwelling as 'a detached, self-contained, small dwelling that may be a stand-alone structure or part of a detached garage and located on the same lot as a larger, principal dwelling.' Section 5.2.7 governs accessory dwellings with these core rules: building footprint may not exceed 50 percent of the principal building footprint; a maximum of one accessory dwelling is permitted per lot; the owner of the lot must be a permanent occupant of the premises (either the principal dwelling or the accessory dwelling, as defined under 'single-family residential' in Chapter 23); exterior stairs, decks, entry doors, and major windows must face the principal building, the alley, the street, or the interior of the lot, and away from adjacent properties where possible; any dormers must be set back a minimum of one foot from the exterior wall; and parking must be provided per Section 10.2 Minimum Parking. The accessory dwelling is treated as an accessory structure for setback purposes, meaning it must comply with the underlying zoning district's accessory structure setback table (typically the same side/rear setbacks as the principal building, sited behind the principal building's front facade per § 5.2). Accessory dwellings count as an accessory structure under the 'subordinate in area and size to the principal building' rule in § 5.2.3. The unit is permitted as a long-term residence (lease, family member, caregiver, or owner) but Franklin's separate Short-Term Rental Ordinance regulates STR use of accessory dwellings — STR-1 (owner-occupied) operation is permitted in residential zones with permit; non-owner-occupied STR-2 use of an accessory dwelling in a single-family zone is generally not permitted. Tennessee has no statewide ADU enabling statute or preemption; Franklin's standards control.