Can Footings Be Poured on Frozen Ground? What Code Says

Short answer: No. Footings may not bear on frozen ground. Wisconsin's dwelling code (SPS 321.16) says footings "may not be placed on frozen material." Minnesota's version of IRC R403.1.4.1 says they "shall not bear on frozen soil." IBC 1809.5 makes one exception, for permanently frozen ground. Thaw the bearing soil first, then pour.

Forum answers to this question usually say "it depends." The codes don't. What depends on the job is how you thaw the ground, how you prove it's thawed, and how you keep it from refreezing before the footing can protect itself.

What do the codes and specs actually say?

Every code and DOT spec we checked prohibits placing footings or concrete on frozen ground. Several also set a minimum temperature for the soil the concrete touches.

For Wisconsin specifically, see our answers on placing footings on frozen ground and frost depth for foundations.

Why can't you pour on frozen ground?

Two things go wrong. ACI 306.1 explains that "a frozen subgrade can lead to freezing of newly-placed concrete or foundation settlement upon subsequent thawing of the subgrade." The frozen soil pulls heat out of the bottom of the footing at the age when it is most vulnerable. Later, when that soil thaws, it can settle under the load.

The first problem damages the concrete itself. ACI 306R-16 says concrete needs about 500 psi before it can survive a single freeze. NRMCA's CIP 27 says concrete that freezes fresh can lose more than 50% of its potential strength and will not be durable.

What about the IBC's "permanent" exception?

It covers permafrost, not a cold week. IBC 1809.5 allows shallow foundations to bear on frozen soil only where "such frozen condition is of a permanent character." Seasonal frost in the upper Midwest or Northeast thaws every spring, so it never qualifies. Minnesota's residential rule drops the exception altogether.

How do you thaw ground for footings?

Heat or insulate the footprint until the bearing soil is unfrozen to the depth the engineer or spec requires, then keep it covered until the pour. ACI 306.1's checklist tells specifiers to state "the depth to which frozen subgrade should be thawed prior to placement of concrete" and how to verify it. If your contract documents are silent, ask the engineer or building official before you pour, and write the answer down.

The usual methods:

• Hydronic ground heaters. ACI 306R-16 defines a hydronic heater as a system "used to heat frozen ground, formwork, or concrete surfaces" by pumping heated fluid through closed-circulation tubing and a heat exchanger.
• Insulating blankets on the excavation. Covering the footprint as soon as it is dug keeps the ground from freezing in the first place, which is far easier than thawing it.
• Heated enclosures. Vent combustion heaters to the outside. ACI 306R-16 notes that heater exhaust can cause dusting of concrete surfaces less than 24 hours old, and the carbon monoxide is a hazard for the crew.

ACI 306.1 also expects the contractor's cold-weather procedure to cover "protecting the subgrade from frost and the accumulation of ice or snow on reinforcement or forms prior to placement."

Thaw-and-pour procedure

1. Plan before you dig. Have blankets or ground heaters on site before excavation. ACI 306.1 section 2.1 requires protection materials on site before cold weather concreting.
2. Cover the excavation the same day you dig it if freezing nights are forecast.
3. Thaw to the required depth. Use the depth in the contract documents, or the one the engineer or building official gives you.
4. Verify and record it. Check the bearing soil before the pour and note how you checked, so you can show the inspector.
5. Clear snow, ice and frost from the excavation, forms and rebar (NYSDOT 555-3.04 A; WisDOT 502.3.9.1).
6. Check contact temperatures. Some specs set a minimum: 35°F for earth under NYSDOT, 40°F under Iowa DOT, above 32°F under ODOT.
7. Order concrete at the right temperature. ACI 306R-16 recommends at least 50°F as placed for sections 12 to 36 inches thick, and 55°F under 12 inches.
8. Protect the footing after the pour. Cover it until it reaches the protection period or strength your spec requires. See how long to keep blankets on new concrete.
9. Don't let the ground under it freeze before backfill. Keep insulation on the footing and the exposed soil around it until the footing is backfilled or the building is enclosed.

What will the inspector check?

On a footing inspection, the frost-related items are depth and what the footing bears on. For Wisconsin dwellings, that means footings below frost penetration or at least 48 inches below adjacent grade (SPS 321.16), and nothing placed on frozen material. Expect the inspector to look for frost, snow, ice and standing water in the excavation. If you thawed the ground, have your record ready: method, duration and how you checked the depth. Requirements vary by jurisdiction and code edition, and the local building official has the final say.

What if the footing freezes after it's poured?

Treat it as damaged until shown otherwise. WisDOT 502.3.9.1 requires contractors to "remove and replace frozen or frost damaged concrete" at their own expense. On a private job, call the engineer of record. In-place testing may show whether the concrete reached 500 psi before it froze. Prevent the problem by keeping the footing covered: ACI 306R-16 Table 7.2 recommends at least 2 days of protection for unloaded concrete that won't be exposed, such as a footing that will be backfilled, and 3 days if it will be exposed to weather.

Asking on site

A crew lead can ask Verika "ground's frozen four inches down, can we pour the footings tomorrow?" and get the answer from the code adopted for that region, the DOT spec if it's a DOT job, and the company's own cold-weather procedure, each cited. For the wider cold-weather rules, see our cold-weather concreting requirements guide and the Wisconsin cold-weather answer.

Sources

1. Wis. Admin. Code SPS 321.16, Frost protection — Wisconsin Legislature (Uniform Dwelling Code)
2. Minn. R. 1309.0403, amending IRC R403.1.4.1 — Minnesota Office of the Revisor of Statutes, effective March 31, 2020
3. Minn. R. 1303.1600, Footing depth for frost protection — Minnesota Office of the Revisor of Statutes
4. Mich. Admin. Code R 408.30449, Frost protection (amends IBC 1809.5) — via Cornell LII
5. Written Interpretation CEB-2021-11-2014 IBC-1809.5 — Indiana Fire Prevention and Building Safety Commission, 2021
6. ACI 306.1-90 (Reapproved 2002), Standard Specification for Cold Weather Concreting, preview and checklists — American Concrete Institute
7. ACI 306R-16, Guide to Cold Weather Concreting (preview: definitions, sections 2.2–4.4) and excerpt (Table 7.2) — American Concrete Institute, 2016
8. CIP 27, Cold Weather Concreting — NRMCA
9. WisDOT Standard Specifications 2025, Section 502 (502.3.5.2, 502.3.9) — Wisconsin DOT
10. NYSDOT Standard Specifications (USC), January 1, 2026, Vol. 2 (555-3.04) — New York State DOT
11. Iowa DOT Standard Specifications, Series 2023 (2403.03 F) — Iowa DOT
12. ODOT Construction and Material Specifications, 2023 (online version 07/17/2026), 511.12 — Ohio DOT