Frostline.info

Frost line depth in Saline County, Missouri

Frost reaches about 31 inches in typical soil across Saline County, from 29″ in the mildest ZIP code to 32″ in the coldest. Codes in this climate commonly set footing depth at 24 to 42 inches.

Deep frost
Estimated frost depth
31″
typical silt/loam soil
Typical code footing depth
24–42″
rule of thumb for this climate
Design freezing index
990
°F-days, 100-year winter
ZIP codes covered
8
#41 of 115 counties in MO (1 = deepest)
31″ 0″12″24″36″48″60″ ground frozen
Est. frost (typical soil) Typical code footing depth Clay–sand range

Frost depth by soil type

Soil typeEst. frost depth
Sand / gravel (drains well)39″
Silt / loam (typical yard soil)31″
Clay (holds water)27″

County average. Methodology.

Verify before you dig. These are climate-based estimates. The legally required frost depth is the figure your building department publishes in its IRC Table R301.2 (climatic and geographic design criteria). Call the Saline County building or permitting office in Missouri and call 811 before digging.

Frost depth by ZIP code in Saline County

ZIPCityEst. frostCode range
65321Blackburn30″24–36″
65330Gilliam32″30–42″
65339Malta Bend31″24–42″
65340Marshall31″24–42″
65344Miami32″30–42″
65347Nelson30″24–42″
65349Slater32″30–42″
65351Sweet Springs29″24–36″

What this means for your project in Saline County

Deck footings & piers

Footings must bear below the frost line and at least 12″ below undisturbed ground. For planning in this area, budget for holes around 42″ deep until your permit office confirms the exact figure.

Fence posts

Set posts at least one-third of their above-ground height. Where frost heave is a problem, carry concrete footings below the frost line (about 31″ here in typical soil) and bell or taper the bottom.

Water & irrigation lines

Bury supply lines below the frost depth. Your water utility or plumbing code sets the minimum cover; in a climate this cold, 4 feet or more is common for service lines.

Slabs & frost-protected foundations

Frost-protected shallow foundations (IRC R403.3) use the 100-year air freezing index — 990 °F-days here — to size perimeter insulation, letting footings sit shallower than the frost line.

Weather stations used

NOAA weather stationDistance100-yr AFI
Sweet Springs, MO16 mi891
Brunswick, MO20 mi1,134
Carrollton, MO22 mi1,015
Boonville Waterworks, MO28 mi938

Nearby counties

Common questions

What is the frost line depth in Saline County?

About 31 inches in typical soil, based on NOAA's 100-year air freezing index. Across the county's ZIP codes the estimate runs from 29 to 32 inches.

How deep should footings be in Saline County, Missouri?

Codes in climates like this commonly require 24 to 42 inches. The Saline County building department publishes the required frost depth in its adopted code (IRC Table R301.2).

Does frost depth vary within Saline County?

Very little. Estimates across the county stay within 3 inches. Soil type matters more than location here.