Frost Line Depth in Shelby County, Tennessee
- Shelby County’s adopted code
- Checked Oct 2026
- Sources
Verified
5in
13 cm · 5 in
Set in the building code Shelby 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: shelbycountytn.gov
Climate: 68 nights a year at or below 32 °F (NOAA 1991–2020, Memphis Wfo, 6.4 mi).
Checked Oct 2026. Report a correction
How deep is the frost line in Shelby County?
Shelby County's building authority sets the frost line depth at 5 in (13 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 Shelby County?
Tennessee leaves the frost line depth to each city or county, and Shelby County fills it in when it adopts the residential code. The value above comes from Shelby County’s own document on shelbycountytn.gov. See how Tennessee sets frost line depth.
How deep do footings, decks and water lines need to be in Shelby County?
House or garage footing in Shelby 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 | 12 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 Shelby County?
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Average lows are at or below freezing from Jan. 68 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 29.9 °F.
NOAA 1991–2020 climate normals, Memphis Wfo station, 6.4 mi away, elevation 310 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 29.9 | 32.7 | 40.1 | 49 | 59.1 | 67.5 | 71 | 69.2 | 61.9 | 49.7 | 39.1 | 32.8 |
| High | 49.4 | 54.1 | 63.1 | 72.7 | 81.1 | 88.4 | 91.3 | 90.7 | 85.3 | 74.6 | 62.1 | 52.4 |
Shelby County has fewer freezing nights than 52 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 Shelby County use?
2 official codes near Shelby County are verified; each links to its document.
| Place | Verified frost line | Distance |
|---|---|---|
| Memphis | 5 in | 7 mi away |
| Madison County | 13 in | 66 mi away |
How likely is the soil in Shelby County to heave?
USDA rates the sampled soil around Shelby County as 100% none for frost action (main soils: Grenada, Udorthents, silty, Memphis).
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?
Shelby County at a glance
- Frost line depth
- 5 in
- Population (2023 est.)
- 910,042
- Mean annual temperature
- 61.1 °F
- ZIP codes (41)
- 38002 · 38004 · 38011 · 38016 · 38017 · 38018 · 38028 · 38029 · 38053 · 38054 · 38103 · 38104 · 38105 · 38106 · 38107 · 38108 · 38109 · 38111 · 38112 · 38113 · 38114 · 38115 · 38116 · 38117 · 38118 · 38119 · 38120 · 38122 · 38125 · 38126 · 38127 · 38128 · 38131 · 38132 · 38133 · 38134 · 38135 · 38138 · 38139 · 38141 · 38152