Outdoor kitchens in Brentwood.

Williamson County sits in the same shallow Southern Tennessee frost band as the rest of the Nashville-Chattanooga corridor, commonly 6 to 12 inches rather than the 18 to 24 inches used further north — but Brentwood is almost entirely built out, so the real gatekeeper on a project inside a community like Governors Club is the HOA's own Architectural Review Committee, a separate approval that runs alongside, not instead of, the county building permit.

Brentwood's median household income is more than double Williamson County's already-high figure, and there's little raw land left — most of the work here is renovation and rebuild on existing large-lot estates rather than new subdivisions.