St. Charles Parish, LA Shrink-Swell Risk

What St. Charles Parish, LA's soil means for a foundation

Very High

USDA's SSURGO data puts St. Charles Parish, LA's soil at "Very High" shrink-swell potential, an area-weighted linear extensibility of 9.88% across 41.4% of the county's surveyed land. Ground that moves this much routinely produces the classic expansive-soil symptoms: diagonal stair-step cracking, doors that stick seasonally, uneven floors. A standard footing is a poor bet here.

This is a county figure, not a lot figure

USDA's survey covers the whole of St. Charles Parish, LA 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 St. Charles Parish will actually do.

Report cost vs. repair cost

Given St. Charles Parish's rating, spending a few thousand now is the way to avoid spending tens of thousands later. The report ($1,000-$5,000) is what tells you whether St. Charles Parish's county-level reading applies to your lot; the repair ($5,000-$15,000) is what it costs if you skip that and find out from the cracks instead.

How St. Charles Parish, LA compares

Nationally, St. Charles Parish, LA is the 32-most-constrained of 3,085 rated counties for shrink-swell soil. Within Louisiana alone it ranks 17 of 64. St. Charles Parish covers 278 square miles and counts 50,400 residents.

See how another county compares

Orleans Parish, LA carries this site's most-constrained reading. Stephens County, TX and Jefferson County, WI are worth a look for comparison.

How this reading is built, and its real limits · The warning signs of expansive-clay damage, explained

More of Louisiana

Every county in Louisiana is on this site, including West Carroll Parish, LA and St. Martin Parish, LA. The full underlying dataset is downloadable directly, one row per county.