Summit County's design-criteria sheet effective July 1, 2026 lists a 36-inch frost-line depth for both its IRC and IBC project-design tables. That number is an important local design input. It is not permission to replace the approved plans with a blanket instruction to make every excavation exactly 36 inches deep.

For a Park City general contractor, the reliable rule is more precise: confirm the governing jurisdiction, follow the stamped design and geotechnical recommendations, meet the applicable frost-protection provisions, and pass the required inspection before placement.

What is actually required in 2026?

Utah law currently incorporates the 2021 International Residential Code for covered residential work and the 2024 International Building Code for covered building work, subject to state and local amendments. The 2021 IRC's Section R403.1.4.1 provides several methods of frost protection for permanent supports. Extending below the locally specified frost line is one method; an approved frost-protected shallow foundation, an ASCE 32 design, or bearing on solid rock may apply in the circumstances the code describes.

That is why “all footings must be exactly 36 inches deep” is an unsupported shortcut. The county's 36-inch frost-line criterion and the project's required footing elevation, width, thickness, reinforcement, and bearing condition answer different questions.

Before excavating, the GC should reconcile:

the site address and authority having jurisdiction;
the current adopted code and amendments;
the county or city design criteria;
the stamped structural details;
the geotechnical report and actual bearing condition; and
any direction from the building official or engineer of record.

Why the approved plan still controls the field scope

A Park City custom home may have stepped footings, frost walls, grade beams, piers, retaining conditions, or engineered details that cannot be reduced to a single frost-depth number. The IRC itself ties footing dimensions to loads and soil-bearing capacity. Its prescriptive minimums are floors, not a project design.

Summit County's inspection policy says the stamped, approved plan must be available on site and followed. It also says structural revisions must be approved by the engineer of record. If excavation reveals fill, water, frozen soil, bedrock, or a bearing condition that differs from the geotechnical assumptions, stop and route that condition to the appropriate design professional rather than improvising a deeper or wider footing.

For a broader view of how the concrete scope fits the structure, see Summit's foundations and footings service and Park City service-area guide.

The inspection sequence can delay a footing before concrete arrives

For projects under Summit County's process, the county's required-inspection checklist places rough-grade engineering controls before the footing inspection. It calls for the footing inspection after steel is in place and before concrete is poured. The county's inspection policies also require the geotechnical report at the footing inspection.

Inside Park City limits, the City's current inspections page tells contractors to resolve required conditional approvals and deferred submittals, keep the approved plans and permit on site, and have the work complete and ready before requesting inspection. Project-specific requirements can vary, so the approved permit set and current inspector direction remain the final field references.

The practical sequence is:

verify erosion-control and rough-grade prerequisites;
complete excavation to the design elevation and expose the intended bearing material;
obtain the required geotechnical observation or report;
install forms, reinforcement, embeds, and grounding components shown in the plans;
request the correct footing inspection within the authority's scheduling rules; and
release the concrete order only after the required approvals are in hand.

Frost line is not the same as frost-free work

Depth is only one part of winter foundation risk. The IRC states that footings must not bear on frozen soil unless the frozen condition is permanent. Fresh concrete also needs cold-weather protection when temperatures during the protection period are expected to fall below the thresholds addressed by the project specifications and ACI guidance.

The American Concrete Institute explains that early freezing can permanently harm fresh concrete. A cold-weather plan may therefore address subgrade condition, concrete temperature, protection, curing, enclosure, monitoring, and the strength evidence needed before protection or forms are removed. These are means-and-methods and specification questions, not a reason to invent a universal calendar ban on Park City pours.

GC pre-pour frost-depth checklist

Jurisdiction: Park City limits, unincorporated Summit County, or another local authority confirmed.
Criteria: current local frost-line value captured in the project file.
Design: stamped footing/foundation details reviewed against the field layout.
Bearing: geotechnical observation and any required report complete.
Condition: excavation free of uncontrolled water and nonpermanent frozen bearing soil.
Reinforcement: size, spacing, support, cover, dowels, and embeds match approved documents.
Inspection: correct inspection passed before the concrete release.
Weather: placement and protection plan matches expected conditions.
Handoff: foundation survey, waterproofing, backfill, framing, and other next steps have named owners.

Source notes

FAQ

Does Summit County require every footing to be exactly 36 inches deep?

No. The county's effective July 1, 2026 design-criteria sheet lists a 36-inch frost-line depth, but the approved design, actual grade, bearing condition, code-compliant frost-protection method, and any applicable exception determine the project detail. Confirm the field elevation with the approved documents and inspector.

Can concrete footings bear on frozen soil?

The 2021 IRC says footings must not bear on frozen soil unless the frozen condition is permanent. A winter placement plan must also protect fresh concrete as required by the approved specifications and conditions.

Who resolves a field condition that differs from the plans?

Document it and route it to the engineer of record, geotechnical professional, and building official as applicable. Summit County's published inspection policy says structural revisions need engineer-of-record approval.

Summit County Frost Depth Requirements: What Every Park City GC Must Build To in 2026