Chatham County, NC Shrink-Swell Risk
Shrink-swell potential in Chatham County, NC
Moderate
Soil across 58.7% of Chatham County, NC comes back "Moderate" in USDA's shrink-swell data, averaging 3.36% linear extensibility. Conventional foundations are the reasonable expectation here, with routine moisture-control practice rather than special engineering.
What this number does and doesn't tell you
This is a countywide, area-weighted figure across every soil survey map unit in Chatham County, NC - never a reading for one specific parcel. A site-specific soil report, usually $1,000-$5,000, is what an engineer would actually pull before designing a foundation on a lot in Chatham County.
Chatham County: the real numbers
Chatham County's soil reading points toward standard foundation practice as the likely outcome, not the exception. 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
Among the 3,085 rated counties on this site, Chatham County, NC ranks 933 most-constrained nationally, and 5 of 100 within North Carolina. The county spans 681 square miles, home to 83,874 people.
See how another county compares
Orleans Parish, LA carries this site's most-constrained reading. Burke County, NC and Clark County, AR 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
Elsewhere in North Carolina
Every county in North Carolina is on this site, including Rutherford County, NC and Halifax County, NC. The full underlying dataset is downloadable directly, one row per county.