How Knoxville Handles Accessory Structures: A Practical Guide

Knoxville maintains 133 local ordinances across all categories, and 3 of those deal specifically with accessory structures. Here is a breakdown of what the city actually requires, what is prohibited, and where Knoxville falls on the strict-to-permissive spectrum compared to other cities.

ADU Rules

Knoxville allows one accessory dwelling unit per single-family lot of at least 5,000 square feet, capped at 40% of the primary home's floor area and two bedrooms, under the zoning code.

Key details: Min lot size: 5,000 sq ft. Max ADU size: 40% of primary dwelling. Max bedrooms: 2 bedrooms. Owner occupancy: One unit owner-occupied required. Citation: Appendix B § 10.3.B.

Adding a second ADU on a lot, building one over 40% of the primary home's floor area, or skipping the owner-occupancy requirement violates Appendix B § 10.3.B and can block a certificate of occupancy.

ADU Owner Occupancy

Knoxville's zoning code requires the property owner to occupy one of the two dwelling units whenever an accessory dwelling unit is added to a single-family lot, tying ADU approval to owner residency.

Key details: Governing section: App. B § 10.3.B.2. Who must live there: The property owner. Applies to: Single-family ADU lots. EN district exception: Neighborhood can opt out.

Zoning Administrator enforcement; violating the ADU standards is a misdemeanor under Knoxville Code § 1-9: up to a $50 fine, $500 in costs, and 30 days' jail, each day a separate offense.

Shed & Carport Rules

Detached accessory structures like sheds in Knoxville are capped at 18 feet tall, need a 5-foot setback from every lot line, and face a lot-size-based coverage cap under the zoning code.

Key details: Max height: 18 feet, capped at house height. Min setback: 5 feet from any lot line. Coverage cap (≤15,000 sf lot): 750 sq ft or less. Coverage cap (1+ acre lot): 1,100 sq ft or less. Citation: Appendix B § 10.3.A.

Building a shed or detached garage taller than 18 feet, inside the 5-foot setback, or over the lot's coverage cap without a variance is a zoning violation enforceable by the Zoning Administrator.

The Bottom Line

Knoxville's accessory structures rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Knoxville is broadly strict or permissive.

This guide is based on Knoxville's current municipal code. Local rules can and do change, so check the individual ordinance pages for the latest details, penalties, and FAQs.