Polk County, MO Shrink-Swell Risk

What Polk County, MO's soil means for a foundation

Low

USDA's SSURGO data puts Polk County, MO's soil at "Low" shrink-swell potential, an area-weighted linear extensibility of 2.75% across 72.8% 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 Polk County, MO 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 Polk County will actually do.

Report cost vs. repair cost

With Polk County, MO 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.

Polk County's rank among Missouri counties

Nationally, Polk County, MO is the 1,374-most-constrained of 3,085 rated counties for shrink-swell soil. Within Missouri alone it ranks 82 of 114. Polk County covers 636 square miles and counts 33,070 residents.

Before you act on this

Orleans Parish, LA carries this site's most-constrained reading. Marion County, TX and Paulding County, OH 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 Missouri

Every county in Missouri is on this site, including Cass County, MO and Johnson County, MO. The full underlying dataset is downloadable directly, one row per county.