Can you build a PSL Modular unit in Tennessee?

The Tennessee Department of Commerce and Insurance, State Fire Marshal's Office, Codes Enforcement Section, through its Modular Building Program. A Construction Inspection Agency (CIA) inspects the unit on the production line and affixes a Tennessee Modular Building Unit Certification Label before it leaves the factory. Manufacturers, dealers and installers must hold a state license and a surety bond. With the label, your local jurisdiction permits the site work — foundation, utilities, zoning — without re-reviewing the structure.

In much of the city, yes — by-right. Nashville's BL2025-1007 (final approval late 2025) makes detached accessory dwelling units permitted by-right in most residential areas of the Urban Services District, removing the special-overlay requirement, and adds a DADU overlay option in the General Services District. Size is capped at the lesser of 1,000 sq ft or 35% of the main home's floor area, generally two stories, with 5-foot rear/side setbacks. You still permit through Metro Codes.

Very. Gatlinburg, Pigeon Forge, and Sevierville form one of the country's largest cabin short-term-rental markets, and modular lets you place a finished cabin quickly on steep mountain lots. The structure clears via the state label; your work is the local/county land-use and short-term-rental ordinance, septic, and steep-slope foundation. Helical piles are common on mountain sites.

In the western part of the state, yes. The New Madrid Seismic Zone runs through West Tennessee near Memphis, one of the more significant seismic risk areas in the eastern US, so units there are engineered to the applicable seismic design category. Most of Middle and East Tennessee is lower risk, where wind and (in the east) light mountain snow matter more.

No. ADUs are governed locally. Nashville is now among the most permissive after BL2025-1007; Knoxville, Chattanooga, and Sevier County have their own rules. Confirm your specific jurisdiction before designing.