Lee's Summit, MO Accessory Structures: Garage Conversions (2026)

The Unified Development Ordinance lists five accepted ways to build an ADU, including an internal conversion of an existing living area, basement, garage, or attic, and an addition to or conversion of an accessory structure such as a detached garage. Right after that list, the ADU development-requirements section adds a specific condition: conversion of an attached or detached garage for an ADU is not permitted unless required parking is provided elsewhere on the property. In practice, a homeowner converting a two-car garage into an ADU has to find replacement off-street parking, such as a widened driveway pad or a new carport, somewhere else on the lot before the conversion is legal.

The ADU itself still has to supply one additional off-street parking space with access to a public or private street, on top of whatever the main house needs. Once the parking condition is met, the converted space is subject to the same size and design limits as any other ADU: a maximum of 1,000 square feet or 50 percent of the principal structure's floor area, whichever is less (500 square feet on smaller Old Downtown lots), a 60 percent cap on total impervious lot coverage, a maximum of two bedrooms, a height that cannot exceed the principal structure's height, and an architectural style compatible with the existing home and neighborhood.