Louisiana

Statewide summary — confirm with your building department before designing

Ultimate design wind speed corrected from 140 to 150 mph by audit. Louisiana does not publish its own parish wind speed table; the State Uniform Construction Code adopts the IRC and IBC and with them the ASCE 7 wind map, so the map value at your site is the requirement. Under ASCE 7-16 at Risk Category II, New Orleans is about 144 mph, Houma about 151, Cameron about 143, Lake Charles about 131, Lafayette about 130 and Baton Rouge about 124, while Grand Isle and the lower delta reach about 163. North Louisiana is far lower, with Shreveport, Monroe and Alexandria at about 105 to 109 mph. The stored 140 mph matched no defensible reading: it under-designed New Orleans and the whole coastal parish belt while grossly over-designing the north. The value published here is the governing contour for the populated Gulf coast parishes; it is deliberately conservative and is not the north Louisiana requirement, and the barrier islands and lower Plaquemines Parish exceed it. This state spans a 2.4 to 1 range in design wind pressure and a site lookup is mandatory. No other value on this row was changed. Ground snow load 0 psf holds for south Louisiana; north Louisiana is 5 psf. Seismic design category A holds throughout the state. Frost depth 0 inches is set locally and was not verified against any government source. The winter design temperature is ASHRAE data, is not published by any Louisiana authority, and is unverified. 2026-08-12 snow-load audit. Louisiana publishes no ground snow load, so min and max are left NULL. Louisiana is structurally unlike most states in that it does have a mandatory statewide construction code: R.S. 40:1730.28 requires the Louisiana State Uniform Construction Code Council to adopt the International Residential Code, excluding only Part I Administration and Part VIII Electrical, and enforcement is mandatory for new construction, reconstruction, additions to homes previously built to the IRC, and extensive alterations. The council's current adoption is the 2021 IRC. Having a real statewide code does not, however, produce a statewide snow number. The full LSUCCC rules and amendments compilation effective 1 August 2025 was read; its residential amendments to Chapter 3 begin at Section R302.1, Exterior Walls, and there is no amendment to Section R301.2 or to Table R301.2(1). The only occurrence of the word snow anywhere in the compilation is in a plumbing amendment about grease interceptors that mentions snowball stands, which is not a design criterion. The climatic and geographic design criteria table is thus left for the local code official to complete, and Louisiana asserts no ground snow load, no range and no parish schedule. For contrast, this is the opposite of how Louisiana treats wind: the statute and the council do engage directly with wind design, amending IRC Section R301.2.1.1 and referencing Figure R301.2(4) thresholds in the farm and accessory structure exemptions in R.S. 40:1730.28. Snow simply is not addressed. Nothing on this row was changed by this pass. The existing observation that ground snow load is 0 psf in south Louisiana and 5 psf in north Louisiana reflects the national map, not any Louisiana instrument, and should be read that way; likewise the stored frost depth of 0 inches remains locally set and unverified against any state source. The wind speed discussion and the 2.4 to 1 range in design wind pressure recorded above stand unaltered and remain the dominant caveat for this state.