Deck Code Requirements in Missouri

Mississippi River corridor (eastern border), Missouri River corridor (central), Meramec River (St. Louis area), numerous tributaries statewide. Missouri has extensive flood risk along Mississippi and Missouri Rivers. 1993 Great Flood caused $15+ billion damage. 2019 floods caused significant damage statewide. State Floodplain Management agency coordinates with local administrators. Verify FEMA maps and local requirements.

Northern Missouri counties where average January temperature is 25F or less (Zone 5A counties and northern Zone 4A). Ice dam risk in northern Missouri. Ice barriers required where IRC is adopted and average January temperature is 25F or below. Verify local requirements - code adoption varies significantly.

Ozarks region: Greene, Christian, Stone, Taney, Barry, Lawrence, Jasper, Newton, McDonald counties, portions of central and southeast Missouri. Missouri has over 6,400 documented caves and extensive karst terrain in Ozarks. Sinkholes can form suddenly. Geotechnical investigation recommended before construction in karst areas. Some jurisdictions require sinkhole assessment.

Southeast Missouri (Bootheel): New Madrid, Pemiscot, Dunklin, Stoddard, Scott, Mississippi, Butler counties and surrounding areas. New Madrid Seismic Zone is one of most significant earthquake hazard areas east of Rockies. 1811-1812 earthquakes estimated at M7.5-8.0 - among largest in US history. 25-40% probability of M6.0+ in next 50 years. Where codes are adopted, SDC D applies. Many rural areas have NO adopted code - verify seismic requirements with AHJ.

Statewide but especially southwest and central Missouri: Jasper, Newton, Greene, Christian, Taney, Webster, Lawrence, Barry counties. 2011 Joplin EF5 tornado killed 158 people - deadliest since 1947. Missouri averages 30+ tornadoes/year. Storm shelters strongly recommended. FEMA safe room grants may be available. Post-Joplin, some jurisdictions strengthened requirements.

Northern and central Missouri counties including: Adair, Andrew, Atchison, Buchanan, Caldwell, Carroll, Chariton, Clark, Clinton, Daviess, DeKalb, Gentry, Grundy, Harrison, Holt, Knox, Lewis, Linn, Livingston, Macon, Marion, Mercer, Monroe, Nodaway, Pike, Putnam, Ralls, Randolph, Schuyler, Scotland, Shelby, Sullivan, Worth counties. Many Missouri counties are EPA Zone 1 (highest radon potential). Testing recommended for all homes. RRNC adds minimal cost to new construction (~$500-1000). Missouri Department of Health provides testing resources.

State with significant severe hail frequency per NOAA SPC storm reports. Insurance restoration contractors should document pre-existing hail damage and recommend impact-resistant materials.