Denver, CO Frost Depth & Snow Load: Building Design Criteria (2026)
Key Facts
- Seismic design category
- B
- Weathering
- Severe
- Wind speed
- 115 / 125 / 140 mph by risk category; special wind region
- Ice barrier underlayment
- Not required
- Winter design temperature
- 1°F; air freezing index 712
- Design elevation
- 5,285 feet, altitude correction factor 0.85
Summary
Denver's design criteria table sets seismic category B, Severe weathering and three wind speeds by risk category, and notably does not require ice barrier underlayment, unlike most snow-belt jurisdictions.
TABLE R301.2 CLIMATIC AND GEOGRAPHIC DESIGN CRITERIA — WIND DESIGN Speed (mph) 115/125/140; Topographic effects No; Special wind region Yes; Wind-borne debris zone No; SEISMIC DESIGN CATEGORY B; SUBJECT TO DAMAGE FROM Weathering Severe, Frost line depth 36 inches, Termite Slight/Mod; WINTER DESIGN TEMP 1°F; ICE BARRIER UNDERLAYMENT REQUIRED No; AIR FREEZING INDEX 712; MEAN ANNUAL TEMP 40-45. MANUAL J DESIGN CRITERIA — Elevation 5,285 feet; Altitude correction factor 0.85.
Full Breakdown
Denver replaces the model code's design criteria table with its own, and several entries are worth knowing before specifying materials. Weathering is classified Severe, which drives the freeze-thaw durability required of concrete and masonry. The seismic design category is B. Wind speed is given as three figures, 115, 125 and 140 mph, corresponding to risk categories rather than a single number, and Denver is flagged as a special wind region while topographic effects and wind-borne debris zone are both marked no. Termite risk is Slight to Moderate. The winter design temperature is 1°F and the air freezing index 712. The entry that most often surprises people arriving from other cold-climate cities is ice barrier underlayment: Denver marks it as not required, where Massachusetts, Connecticut, Rhode Island and every Indiana county require it. Denver's Manual J criteria are calculated at an elevation of 5,285 feet with an altitude correction factor of 0.85.
Violations & Fines
These criteria are enforced at plan review and inspection rather than as offences in themselves. The specific trap in Denver is assuming the ice barrier requirement carries over from another snowy jurisdiction and pricing it in, or conversely assuming a single wind speed where the table gives three by risk category.
Frequently Asked Questions
Does Denver require ice barrier underlayment?
What wind speed applies in Denver?
What weathering classification applies?
Sources & Official References
Other rules in Denver
Compare Denver to another location·View the Colorado frost depth & snow load overview
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