Sullivan County, NH Shrink-Swell Risk

Sullivan County, NH's soil, for shrink-swell risk

Low

Sullivan County, NH: USDA's soil survey rates 98.1% of the county "Low" for shrink-swell potential (0.84% linear extensibility). That's the easiest starting point on this site's scale - a standard foundation is the reasonable default here, though any one lot can still differ.

What Sullivan County's reading doesn't cover

Two lots a mile apart in Sullivan County can carry different soil, even though they share one countywide reading. 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 Sullivan County.

What it costs to find out, versus to ignore it

With Sullivan County, NH 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.

Where this sits nationally

Nationally, Sullivan County, NH is the 2,966-most-constrained of 3,085 rated counties for shrink-swell soil. Within New Hampshire alone it ranks 7 of 10. Sullivan County, NH is 538 square miles with a population of 44,012.

For contrast

Orleans Parish, LA carries this site's most-constrained reading. Bates County, MO and Rhea County, TN 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 New Hampshire

Every county in New Hampshire is on this site, including Hillsborough County, NH and Strafford County, NH. The full underlying dataset is downloadable directly, one row per county.