Frost Line Depth in Shelby County, KY: 24 in (Kentucky rule)

State-set value

24in

61 cm · 2 ft

24 in (Kentucky rule)

Set by the state: Kentucky Residential Code Table R403.1.4, all other counties.

Source and how we checked

Shelby County does not publish its own value; the state rule applies.

Document: codes.iccsafe.org

Climate: 139 nights a year at or below 32 °F (NOAA 1991–2020, Shelbyville 1 E, 3.1 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

139nights a year at or below 32 °F
45%of nearby soil rated “high” for frost action (USDA)

How deep is the frost line in Shelby County?

Kentucky sets the frost footing depth for Shelby County at 24 in (61 cm). Footings, piers and other permanent supports must reach at least this depth (IRC R403.1.4.1).

Who sets the frost line depth in Shelby County?

Kentucky writes this depth into its statewide residential code, so Shelby County’s building department enforces the state’s number rather than setting its own. See how Kentucky sets frost line depth.

How deep do footings, decks and water lines need to be in Shelby County?

House or garage footing Deck footing Water service line Fence post

House or garage footing in Shelby County: dig at least 24 in (61 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).

Minimum depths in Shelby County with a 24 in frost line
Project	Depth	Rule
House or garage footing	24 in	Below the frost line and at least 12 in deep (IRC R403.1.4)
Deck footing (attached)	24 in	Below the frost line and at least 12 in deep (IRC R507.3)
Water service line	30 in	6 in below the frost line and at least 12 in deep (IRC P2603.5)
Fence post bottom	24 in	No code rule; common practice is below the frost line

Work out posts, concrete and footing sizes with the fence post depth calculator or the deck footing calculator.

How cold does it get in Shelby County?

Average lows are at or below freezing from Nov to Mar. 139 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 20.3 °F.

NOAA 1991–2020 climate normals, Shelbyville 1 E station, 3.1 mi away, elevation 730 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	20.3	21.3	28.7	37.5	49.3	58.2	62.3	58.4	50.3	40.4	29.6	24.1
High	41.7	47.1	56.9	67.8	76.9	85.3	87.6	87	81	69.3	56.5	45.7

Shelby County has more freezing nights than 20 of the 20 other Kentucky places we track. The Kentucky median is 90. Coldest: Shelby County; mildest: Barren County.

How likely is the soil in Shelby County to heave?

Moderate 44%High 45%

USDA rates the sampled soil around Shelby County as 11% none, 44% moderate, 45% high for frost action (main soils: Shelbyville, Lowell, Water).

USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.

How do you confirm the frost line before you dig in Shelby County?

Call 811 at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Shelby County building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 24 in unless the building department tells you otherwise.
Book the footing inspection before you pour concrete.

Shelby County at a glance

Frost line depth: 24 in (Kentucky rule)
Population (2023 est.): 49,515
Mean annual temperature: 53.5 °F
ZIP codes (14): 40003 · 40019 · 40022 · 40023 · 40046 · 40057 · 40065 · 40067 · 40068 · 40071 · 40076 · 40245 · 40342 · 40601