Wyoming

Statewide summary — confirm with your building department before designing

Seismic design category corrected from A to B. Not one populated place checked in Wyoming reads A. The USGS ASCE 7-16 design maps service, read at Site Class D and Risk Category II under the IRC single parameter method, returns short period design accelerations of 0.172 g at Cheyenne, 0.323 g at Casper, 0.270 g at Laramie, 0.246 g at Gillette and 0.274 g at Sheridan, all category B, and then climbs westward to 0.335 g at Rock Springs, 0.340 g at Cody, 0.356 g at Riverton and 0.749 g at Jackson. Two Wyoming jurisdictions confirm the higher end from their own adopted tables: Teton County states that its minimum seismic design category is D and identifies D sub one and D sub two, and the City of Riverton adopted C. The stored A was below the actual requirement at every one of Wyoming's largest communities. B is set here because it covers Cheyenne, Casper, Laramie, Gillette and Sheridan, the five largest, but western Wyoming needs C and Teton County needs D, and Cheyenne clears the A to B threshold by only a hair, so this row should be read as a floor and never as a substitute for the local table. Termite risk of none is confirmed correct: both Teton County and Riverton adopted the IRC none to slight band. Two other values were left alone. Ground snow load of 40 psf is untenable as a single number for this state and no better scalar exists, because Riverton adopted 30 psf while Teton County maps its ground snow loads at 120 psf and 175 psf, and no one figure informs both. Frost depth of 48 inches exceeds both adopted values found, 30 inches at Riverton and 34 inches in Teton County, so it over builds rather than under builds and was not changed. Wind speed of 110 mph likewise sits above the 105 mph adopted by Teton County and the 100 mph adopted by Riverton, though Wyoming contains special wind regions where local topographic speed up drives requirements far higher. Winter design temperature is unestablished statewide; Teton County adopted minus 30 F against the stored minus 15. Confirm your own lot with the local building official. Sources: https://earthquake.usgs.gov/ws/building-codes/, https://tetoncountywy.gov/DocumentCenter/View/21049/171-2021-Building-code-amendments and https://cms2.revize.com/revize/rivertonwy/departments/docs/Climatic%20and%20Geographic%20Design%20Criteria%202025.pdf SNOW LOAD AUDIT 2026-08-12 (physical design data pass). Minimum and maximum both left NULL. Wyoming publishes no statewide ground snow load, and this audit proved it by reading the only state building-code rule that exists. That rule is Chapter 1, General Provisions, of the rules of the Department of Fire Prevention and Electrical Safety, adopted by the Council on Fire Prevention and Electrical Safety in Buildings under W.S. 35-9-106(a) and amended on adoption 23 April 2024. The whole chapter runs two pages. Section 2 incorporates by reference the 2024 editions of the International Building Code, International Existing Building Code, International Fire Code including appendices D, E, F and G, International Mechanical Code and International Fuel Gas Code, and picks up the International Residential Code, the International Property Maintenance Code, the International Plumbing Code and the International Energy Conservation Code only to the extent those are referenced within chapters 1 through 10 of the IBC, IFC, IMC and IFGC. There is not one Wyoming amendment to any climatic or geographic design criterion, and the word snow does not appear. The rest of the filing is the certification page, the statement of reasons and the fiscal forms. Silent-failure check: the final filed rule PDF on wyoleg.gov has no usable text layer, so the adopted Chapter 1 pages were rendered at high resolution and read visually rather than searched as text. The rendered text matches the machine-readable proposed version filed in the same docket, which shows the 2021 edition years struck through and replaced with 2024 and no other substantive change. The scope of that rule matters as much as its content. Wyoming has no statewide building code for private construction. The State Fire Marshal plan review reaches only the buildings listed in W.S. 35-9-108: state and local government owned or leased buildings, schools, buildings over 5,000 square feet in total area with public access, child care centres for more than ten children, multi-story buildings and places of assembly of any size, together with fire protection systems, alternative energy installations, above ground storage tanks, commercial kitchen hoods, spray finishing and site plans for parks. One and two family dwellings are not on that list and are not covered anywhere by state law. No value on this row was changed by this pass. The previous audit's correction of the seismic design category from A to B stands, and everything it recorded about the other three values still holds and is now framed correctly: those figures come from local jurisdictions, not from Wyoming, because Wyoming has nothing to give. Riverton adopts a 30 psf ground snow load, a 30 inch frost depth and 100 mph wind; Teton County maps ground snow loads at 120 and 175 psf, adopts 34 inches of frost, 105 mph wind and a minimum seismic design category of D. Those two numbers, 30 and 175, are the widest pair of officially adopted Wyoming ground snow loads this project has seen, but they are county and municipal figures rather than a state range, so they were not written into the min and max columns.