Robertson County, TN Shrink-Swell Risk
What Robertson County, TN's soil means for a foundation
Low
USDA's SSURGO data puts Robertson County, TN's soil at "Low" shrink-swell potential, an area-weighted linear extensibility of 2.07% across 89% of the county's surveyed land. That's as favorable a county-level reading as this dataset produces - standard foundation practice, pending one lot's own geotechnical report.
This is a county figure, not a lot figure
USDA's survey covers the whole of Robertson County, TN at once, not any single address. A local geotechnical report, typically $1,000-$5,000 (around $2,700 typical), is the only way to know what one lot in Robertson County will actually do.
Report cost vs. repair cost
With Robertson County, TN rating "Low", a geotechnical report is still worthwhile before a build, just less urgent than in a high-risk county. A geotechnical report runs $1,000-$5,000, typically around $2,700. Foundation repair, if a specific lot turns out to differ from the county average, runs $5,000-$15,000.
Where this sits nationally
Nationally, Robertson County, TN is the 1,913-most-constrained of 3,085 rated counties for shrink-swell soil. Within Tennessee alone it ranks 47 of 95. The county spans 476 square miles, home to 78,459 people.
See how another county compares
Orleans Parish, LA carries this site's most-constrained reading. Clark County, ID and Guthrie County, IA are worth a look for comparison.
How this reading is built, and its real limits · Moisture management: the cheap fix that works on any soil
More of Tennessee
Every county in Tennessee is on this site, including Lawrence County, TN and Morgan County, TN. The full underlying dataset is downloadable directly, one row per county.