Missouri

Statewide summary — confirm with your building department before designing

Seismic design category corrected from A to D by audit. No location in Missouri is SDC A. Under ASCE 7-16 at Site Class D and Risk Category II the St. Louis metropolitan area is D, Kansas City and St. Joseph are B, Springfield and Columbia are C, and the New Madrid seismic zone in the southeast is far higher: Cape Girardeau and Poplar Bluff are D1 and Sikeston, New Madrid, Kennett and Caruthersville are E, with mapped short-period spectral response acceleration above 1.5 g and in places above 2 g. D is published here because it governs the state largest metropolitan area, but it is not safe to use anywhere in the Bootheel and it is conservative for Kansas City. Seismic design category depends on site class and risk category as well as location, so a site-specific determination is always required. No other value on this row was changed. Wind speed 105 mph is the ASCE 7-16 interior base contour for ultimate design wind speed at Risk Category II; Missouri site values interpolate to roughly 106 to 110 mph. Ground snow load 20 psf matches St. Louis, Kansas City and Columbia under ASCE 7-16; southwest and southeast Missouri are 15 psf and the Bootheel 10 psf. Frost depth 36 inches is set locally in Missouri and was not verified against any government source. The winter design temperature is ASHRAE data, is not published by any Missouri authority, and is unverified. 2026-08-12 snow-load audit. Missouri publishes no ground snow load, so min and max are left NULL, and in Missouri's case the phrase "the state value" is a fiction in the strongest sense of any state in this group: there is no statewide building code to carry such a value. Building regulation is delegated to local government. RSMo 64.170 empowers the county commission in first and second classification counties to adopt regulations controlling the construction, reconstruction, alteration or repair of buildings and structures, and adds that a county which had not adopted a code by 28 August 2001 must first obtain the approval of the voters of its unincorporated area. RSMo 67.280 is purely procedural, letting a county, fire district or municipality that already possesses the authority incorporate a technical code by reference provided copies are filed with the clerk ninety days beforehand. Neither statute sets any design criterion. That no statewide code exists is corroborated by the repeated legislative attempts to create one: House Bill 2870 of the 2024 session would have enacted a Missouri Building Codes Act, created Missouri Building Codes and a Missouri Building Codes Commission within the Division of Fire Safety, and required authorities that had already adopted codes to adopt the new ones. It did not become law. The single state-level construction standard in Missouri was checked directly and does not supply a snow load either. The Public Service Commission's modular unit rules at 20 CSR 4240-123 adopt a residential code by reference for factory-built modular units, and 20 CSR 4240-123.080(5) requires every modular unit to meet or exceed the seismic zone requirements, A, B, C, D1, D2 or E, for the area in which it is placed. That provision is itself official confirmation that Missouri spans the full seismic range. The rule contains no reference to snow anywhere and fixes no ground snow load. Nothing on this row was changed by this pass. The stored ground snow load of 20 psf, wind speed of 105 mph, seismic design category D and frost depth of 36 inches are all derived, not published by Missouri, and the caveats recorded above stand: category D is not safe anywhere in the Bootheel, where the New Madrid counties compute to E, and is conservative for Kansas City.