Foundations
How deep do footings have to go in Fremont County? Thirty-two inches.
Published · every figure below was checked against its primary source on the date shown.
One number, the whole county
Thirty-two inches, and it does not move. Fremont County states the requirement in a single sentence:
“Section 4. Minimum Frost Depth for Footings: The minimum frost depth for footings shall be 32 inches.”
— Fremont County Ordinance No. 2005-02, Section 4 (county-published PDF, retrieved 13 August 2026)
What makes this worth its own page is the contrast with the other number in the same ordinance. The ground snow load is split into districts with different values; the frost depth is stated once, countywide. Your lot’s location changes one and not the other.
Why the ground gets a say in your foundation
Soil holding water expands when it freezes, and it does not expand evenly. A footing bearing above that zone gets lifted in winter and dropped in spring, repeatedly, and everything fastened to it — walls, windows, tile, drywall — records the movement. Placing the bearing surface below the frost line removes the mechanism.
Where the 32 inches shows up in a bid
| Line | Effect | Scales with |
|---|---|---|
| Excavation volume | Deeper trench or deeper full dig for the bearing surface. | Footprint perimeter and area |
| Foundation wall | More wall between footing and floor level — concrete, forms and labour. | Perimeter length |
| Backfill and compaction | More material moved, replaced and compacted. | Excavated volume |
| Schedule | The pour has to happen inside the workable-ground window. | Season, not size |
A sprawling single-storey plan pays this line harder than a compact two-storey one of the same floor area, because the cost follows perimeter rather than square footage. It is one of the few design decisions that visibly changes a foundation bid.
What to confirm before the excavator arrives
- The number your engineer specified, which may be deeper than 32 inches for your soils. Where it is, that figure governs.
- That every bidder priced the same depth. This is a classic quiet difference between two foundation quotes — one of several worth pinning down in writing.
- The inspection sequence with the county building department, so the pour is not held waiting.
- The calendar. Frozen ground is a scheduling constraint that costs money through delay rather than through price.
- Whether backfill and compaction are in the same bid as the excavation, or quoted separately by someone else. Deeper digs move more material both ways.
- What happens if the soil differs from the assumption. Ask how a change is priced before it is discovered, not after the machine is already on site.
Related reading on this site
- The 90 PSF question — the other ordinance figure, and the one that does vary by district
- The county permit path — where foundation inspections sit in the file
- What a build costs here — how foundation depth reaches your budget
- The builder table — the firms running these foundations
Common questions
How deep do footings have to be in Fremont County?
At least 32 inches. Fremont County Ordinance No. 2005-02 sets a minimum frost depth for footings of 32 inches, and it is written as a countywide figure rather than varying by district the way the snow load does.
Does the 32-inch minimum change between Ashton and the rest of the county?
No. Unlike the ground snow load, which the same ordinance splits into districts with different values, the frost depth is stated once and applies across the county. It is one of the few numbers here that does not depend on where your lot sits.
Is 32 inches the depth of the hole or the depth of the footing?
It is the depth to the footing — the bottom of the foundation has to sit at or below that line so the bearing surface is under the frost. The excavation is necessarily deeper than the footing itself, which is why it shows up as excavation volume in a bid.
Why does frost depth matter structurally?
Because soil that freezes expands, and soil that expands under a footing lifts it. Frost heave moves foundations unevenly, and an unevenly moved foundation cracks everything attached to it. Getting the bearing surface below the freeze line is what prevents that.
What does it cost me?
It shows up in two places: excavation volume, and foundation wall height. Both scale with the footprint of the house, so it is a larger line on a sprawling single-storey plan than on a compact two-storey one with the same floor area.
Can I pour footings late in the season?
Up to a point, and the ground decides where that point is. Concrete has requirements about placing against frozen ground and curing temperatures, and once the soil is frozen the excavation itself becomes slow and expensive. It is a scheduling constraint more than a prohibition.
Does a shop or a detached garage need the same depth?
If it is a permitted structure with footings, the same county minimum applies. Whether your particular outbuilding needs a permit at all is a separate question the county publishes a threshold sheet for.
Who confirms my foundation meets it?
The county building department, through inspection, on (208) 624-7200. The figure is a minimum in the ordinance; your engineer or designer may specify deeper for your soils, and where they do, theirs is the number that governs.