Logan County, IL Shrink-Swell Risk

Logan County, IL's soil, for shrink-swell risk

Moderate

Logan County, IL: USDA's soil survey rates 93% of the county "Moderate" for shrink-swell potential (4.15% linear extensibility). That's a middle reading: not the sharp swings that crack a foundation outright, but enough that grading and drainage are worth getting right.

What Logan County's reading doesn't cover

Two lots a mile apart in Logan County can carry different soil, even though they share one countywide reading. The real answer for one lot is still a site-specific geotechnical report, running about $1,000-$5,000 (typically near $2,700).

What it costs to find out, versus to ignore it

With Logan 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.

Logan County's rank among Illinois counties

Nationally, Logan County, IL is the 497-most-constrained of 3,085 rated counties for shrink-swell soil. Within Illinois alone it ranks 24 of 101. The county spans 618 square miles, home to 27,518 people.

For contrast

Orleans Parish, LA carries this site's most-constrained reading. Kiowa County, CO and Kay County, OK 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 Rock Island County, IL and Lake County, IL. The full underlying dataset is downloadable directly, one row per county.