ADU (Accessory Dwelling Unit) permit in Knoxville, TN
Yes — you need a permit for adu (accessory dwelling unit) work in Knoxville.
Building an accessory dwelling unit (garage apartment, casita, etc.) is new residential construction and needs a building permit; a dwelling unit is never covered by the small detached-accessory-structure exemption. Zoning approval also applies, and ADUs are a recognized accessory use in RN districts.
| Permit needed? | Yes |
|---|---|
| Where the line falls | Building an accessory dwelling unit (garage apartment, ca… |
| Fee | Building permit fees are set in the city Fee Schedule adopted by City Council resolution; the code lists no fixed amount. |
| Review time | Not in the ordinance |
| Code section | IRC R105.1 (permit required for construction); R105.2 does not exempt a dwelling unit |
| Based on | Tennessee-adopted IRC 2018, as amended by City of Knoxville; ADU recognized as an accessory use in the zoning code (4.2 Uses) |
How to pull the permit
- Put together a site plan showing where the work goes, with dimensions.
- Apply through the Knoxville building department.
- Pay the permit fee when the permit is issued. Work done before that isn't covered.
- Book each inspection listed on the permit as the job reaches that stage.
If you skip it
Starting building work before the permit is issued means extra fees on top of the required permit fee (Section 109.4 as amended).
Nearby cities, same job
Rules stop at the city line. If your lot is near a boundary, or you work across several towns, this is where they differ.
| City | Distance | Permit? | Where the line falls |
|---|---|---|---|
| Knoxville | — | Yes | Building an accessory dwelling unit (garage apartment, ca… |
| Farragut | 14 mi | Yes | No size threshold in the code |
| Morristown | 40 mi | Yes | No size threshold in the code |
| Kingsport | 87 mi | Yes | No size threshold in the code |
| Johnson City | 91 mi | Yes | Building an accessory dwelling unit (garage apartment, ca… |
| Chattanooga | 96 mi | Yes | Building a garage apartment, casita, or other accessory d… |
See every Tennessee city on adu (accessory dwelling unit) work
Other work in Knoxville
Questions people ask
How much does a adu (accessory dwelling unit) permit cost in Knoxville?
Building permit fees are set in the city Fee Schedule adopted by City Council resolution; the code lists no fixed amount.. Valuation-based fees mean the number depends on what the job is worth, so the department quotes it when you apply.
I already built it without a permit. What now?
Knoxville can issue a stop-work order and require you to apply after the fact, sometimes with an extra fee. Work that was covered up may have to be opened for inspection. Full walkthrough here.
Does unpermitted work cause problems when selling the house?
Often, yes. A buyer's inspector or the title company may flag it, and lenders can balk at financing a home with open or missing permits. What to do about it.