Remnant Architecture

Are you thinking about adding an accessory dwelling unit (ADU) to your property? An ADU would be a separate building from your house that has space for living, sleeping, cooking, and bathing. You might also call it a backyard/garage apartment, guest house, granny flat, in-law suite, or tiny home.

You will need to check is whether building an ADU is allowed by your jurisdiction, as many localities still favor single-family houses only in residential zoning. Since Remnant Architecture works in Knoxville, TN, this article is about the requirements for the City of Knoxville, Knox County, and the Town of Farragut. If you live in an HOA, you will want to check their requirements as well.

City of Knoxville

The City of Knoxville recently updated its zoning ordinance to be more ADU friendly to open up more housing options.

You are allowed one ADU on a lot with a single-family house. The property owner must occupy either the single-family house or the ADU. Your lot must be at least 5,000 square feet to have an ADU. The ADU cannot be in front of your house but can be beside or behind your house. Typically an ADU must be setback at least five feet from your rear and side property lines, though your specific zoning district may require more.

The maximum footprint for an ADU depends on the size of your house/lot and is typically between 750 to 1,100 square feet. The maximum height of an ADU is 18 feet, which is measured from the ground to halfway up the roof. You are allowed a maximum of two bedrooms. A bathroom with shower/tub and kitchen with range are required in the ADU. You will also need to provide an off-street parking space for the ADU, either in a garage or on a driveway.

Knox County

Much of the current Knox County zoning ordinance hasn’t been updated in decades. The County is currently in the process of a comprehensive update, which is proposed to be adopted in 2026. Below is currently how ADUs stand in the County.

Garage apartments are what is typically allowed for an ADU. That would mean the ADU would be the second story above the garage. Garage apartments are permitted by right (meaning you don’t have to have it approved at a planning commission meeting) in the RB (General Residential), A (Agricultural), and E (Estates) Zones. Garage apartments are permitted on review (meaning the planning commission will have to approve it at a public meeting) in the RA (Low Density Residential) Zone. Garage apartments are not allowed in the RAE (Exclusive Residential) and PR (Planned Residential) Zones.

The garage apartment will have restrictions in height, setbacks, footprint, and minimum lot size depending on the zone.

Town of Farragut

The Town of Farragut tends to be pro-single-family housing so there are not many opportunities for ADUS there. However, if the community determines there is a need for ADUs in the future, they can bring it to the town officials to propose an amendment to the ordinance.

ADUs are allowed in the A (Agricultural) and R-1 (Rural Single-Family Residential) Districts. They are treated as a second house, rather than an accessory building, so the setback requirements are greater than the City of Knoxville or Knox County. There are also minimum lot sizes that must be met for an ADU, depending on the zoning.

ADUs are not allowed in R-2 (General Single-Family Residential), OSR (Open Space Residential Overlay), and R-3 (Small Lot Single-Family Residential) Districts.

Need help designing an ADU? Fill out the new client application to work with Remnant Architecture.