Shelby County, IL Shrink-Swell Risk
Shelby County, IL's soil, for shrink-swell risk
Moderate
Shelby County, IL: USDA's soil survey rates 70% of the county "Moderate" for shrink-swell potential (3.94% linear extensibility). A real but modest amount of movement - standard foundations usually hold up, but drainage and moisture control around the foundation still matter more than on low-risk soil.
What Shelby County's reading doesn't cover
Two lots a mile apart in Shelby County can carry different soil, even though they share one countywide reading. A local geotechnical report, typically $1,000-$5,000 (around $2,700 typical), is the only way to know what one lot in Shelby County will actually do.
What it costs to find out, versus to ignore it
With Shelby County, IL rating "Moderate", 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.
How Shelby County, IL compares
Nationally, Shelby County, IL is the 604-most-constrained of 3,085 rated counties for shrink-swell soil. Within Illinois alone it ranks 35 of 101. The county spans 759 square miles, home to 20,542 people.
Before you act on this
Orleans Parish, LA carries this site's most-constrained reading. Benton County, AR and Pratt County, KS 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 Illinois
Every county in Illinois is on this site, including Stephenson County, IL and Vermilion County, IL. The full underlying dataset is downloadable directly, one row per county.