Putnam County, TN Shrink-Swell Risk
Shrink-swell potential in Putnam County, TN
Low
Soil across 76.9% of Putnam County, TN comes back "Low" in USDA's shrink-swell data, averaging 2.2% 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 this number does and doesn't tell you
This is a countywide, area-weighted figure across every soil survey map unit in Putnam County, TN - 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 Putnam County.
Putnam County: the real numbers
Putnam 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, Putnam County, TN ranks 1,797 most-constrained nationally, and 39 of 95 within Tennessee. The county spans 401 square miles, home to 84,894 people.
For contrast
Orleans Parish, LA carries this site's most-constrained reading. Androscoggin County, ME and Green County, WI 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 Tennessee
Every county in Tennessee is on this site, including Sequatchie County, TN and Rhea County, TN. The full underlying dataset is downloadable directly, one row per county.