Southlake council narrows transition zoning rules, tightens adjacency standards

The Southlake City Council on April 15 approved changes to Section 47 of the city27s zoning ordinance that revise development standards for the Transition Zoning District, a category used for mixed residential and nonresidential projects.

City planners said the amendments clarify how density is calculated and add new adjacency protections for established single-family neighborhoods. Director Killough described the changes during a work session and second reading, explaining the setback structure the draft ordinance proposed: "a minimum setback would be provided of 50 feet for a 1 story building, 70 feet for a 2 story building, and 90 feet minimum for a 3 story building," language the council later modified to permit a maximum of two stories for nonresidential buildings adjacent to single-family zones.

Why it matters: The TZD is used where different land uses meet; the amendments are intended to reduce conflicts between newer, denser developments and older, low-density neighborhoods. Councilmembers said the changes respond to concerns raised in recent development cases where neighbors asked for clearer protections.

Key changes approved - Setbacks and height: For nonresidential components that directly abut single-family zoning, the ordinance now requires a 50-foot minimum building setback for one-story structures plus an additional 20 feet for each additional story; council amended the approval to limit nonresidential building height to two stories in adjacency situations. - Residential adjacency protections: The council directed staff to add a stepped lot-size requirement when new residential lots directly abut existing residential lots: where a TZD proposal would touch an existing one-acre (or larger) lot, the lots immediately adjacent must be at least 30,000 square feet; where they would abut a 30,000-square-foot lot, the adjacent lots must be at least 20,000 square feet. - Buffers and screening: A minimum 10-foot F-1 type buffer yard or a solid evergreen vegetative screen that reaches 8 feet within three years is required along residential adjacencies, plus mechanical and trash screening and specified distances for trash enclosures. - Open-space and detention: Detention basins are excluded from open-space credit unless they are designed as aesthetic, passive recreational amenities and are approved by staff and city council; the ordinance includes guidance (preferred slope, walking loops, native planting) for amenity-style basins.

Council discussion and vote Deputy Mayor Pro Tem Randy Williamson moved approval of the second-reading ordinance with amendments; the motion passed 6-0. Williamson said the amendments strike a balance between allowing transition districts to redevelop and protecting long-established neighborhoods.

What remains for implementation City staff will incorporate the council27s direction into revised ordinance language and apply the new adjacency rules to future TZD applications. The amendments also preserve existing TZD districts as they were approved previously; only newly proposed TZD developments are subject to the new standards.

Evidence: Director Killough led the presentation and described the new adjacency standards during the work session and second-reading debate. Mayor Pro Tem Williamson moved approval and the council voted 6-0 to adopt the changes.