Frost Line Depth in Blount County, Tennessee
- Blount County’s adopted code
- Checked Oct 2026
- Sources
Verified
10in
25 cm · 10 in
Set in the building code Blount County has adopted.
Footings still go at least 12 in (30 cm) below undisturbed ground (IRC R403.1.4).
Source and how we checked
Document: blounttn.gov
Climate: 67 nights a year at or below 32 °F (NOAA 1991–2020, Knoxville Mcghee Tyson Airport, 9.6 mi).
Checked Oct 2026. Report a correction
How deep is the frost line in Blount County?
Blount County's building authority sets the frost line depth at 10 in (25 cm). Footings, piers and other permanent supports still go at least 12 in below undisturbed ground (IRC R403.1.4).
Who sets the frost line depth in Blount County?
Tennessee leaves the frost line depth to each city or county, and Blount County fills it in when it adopts the residential code. The value above comes from Blount County’s own document on blounttn.gov. See how Tennessee sets frost line depth.
How deep do footings, decks and water lines need to be in Blount County?
House or garage footing in Blount County: dig at least 12 in (30 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).
| Project | Depth | Rule |
|---|---|---|
| House or garage footing | 12 in | Below the frost line and at least 12 in deep (IRC R403.1.4) |
| Deck footing (attached) | 12 in | Below the frost line and at least 12 in deep (IRC R507.3) |
| Water service line | 16 in | 6 in below the frost line and at least 12 in deep (IRC P2603.5) |
| Fence post bottom | 12 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 Blount County?
- J
- F
- M
- A
- M
- J
- J
- A
- S
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- N
- D
Average lows are at or below freezing from Jan. 67 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 30 °F.
NOAA 1991–2020 climate normals, Knoxville Mcghee Tyson Airport station, 9.6 mi away, elevation 962 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 30 | 33.1 | 39.8 | 48 | 56.9 | 64.9 | 68.7 | 67.5 | 61.1 | 48.9 | 38.1 | 32.8 |
| High | 48.2 | 52.8 | 61.4 | 71.2 | 78.9 | 85.7 | 88.4 | 87.8 | 82.5 | 71.7 | 60 | 51 |
Blount County has fewer freezing nights than 55 of the 59 other Tennessee places we track. The Tennessee median is 84. Coldest: Greene County; mildest: Memphis.
What frost line depth do towns near Blount County use?
2 official codes near Blount County are verified; each links to its document.
| Place | Verified frost line | Distance |
|---|---|---|
| Loudon County | 12 in | 22 mi away |
| Bradley County | 12 in | 64 mi away |
How likely is the soil in Blount County to heave?
USDA rates the sampled soil around Blount County as 91% none, 9% moderate for frost action (main soils: Ramsey, Dewey, Tellico).
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 Blount County?
Blount County at a glance
- Frost line depth
- 10 in
- Population (2023 est.)
- 141,456
- Mean annual temperature
- 59.5 °F
- ZIP codes (13)
- 37701 · 37737 · 37742 · 37777 · 37801 · 37803 · 37804 · 37853 · 37865 · 37878 · 37882 · 37886 · 37920