Flashing Code Requirements in North Dakota

All of North Dakota is Seismic Design Category A per ASCE 7 and IBC. Minimal seismic risk. No special seismic design requirements beyond standard construction.

Ice barrier underlayment REQUIRED statewide for all roofing projects per IRC R905.1.2 and Table R301.2(1). North Dakota is designated as an area with history of ice forming along eaves causing water backup. Must extend minimum 24 inches inside exterior wall line. Required at eaves, valleys, and penetrations.

Buildings used for agricultural purposes are exempt from building code requirements per N.D.C.C. § 54-21.3-04(3), unless the building is a place of human habitation or for use by the public.

Nearly all of North Dakota falls within EPA Radon Zone 1, with predicted indoor screening levels above 4 pCi/L. Glacial till deposits overlying Pierre Shale bedrock are the primary radon source. North Dakota Department of Health tracks radon data by county. IRC R324 radon-resistant new construction is strongly recommended statewide. Cass, Burleigh, and Ward counties have particularly high testing rates.

North Dakota experiences 20-30 tornadoes annually, primarily from June through August. The southeast corner (Cass, Richland, Ransom counties) has the highest tornado density. The 1957 Fargo tornado (F5) remains one of the most studied in history. Enhanced wind design per ASCE 7-22 and safe room provisions per ICC 500/FEMA P-361 are recommended for new residential construction.

North Dakota lies in the northern Great Plains hail belt with 30+ severe hail events per year. Southwestern North Dakota (Slope, Bowman, Adams counties) has the highest hail frequency. Roofing materials should meet UL 2218 Class 4 impact resistance. Crop and property hail damage costs the state millions annually. Insurance carriers commonly require impact-resistant roofing.

Western North Dakota contains bentonite clay deposits (from volcanic ash alteration) that are among the most expansive soils in North America. Slope, Golden Valley, Billings, and Stark counties have the highest concentrations. Soil swelling pressures can exceed 10,000 psf. Foundation design per IBC 1808.6 requires deep piers, moisture barriers, or structurally isolated slabs.

The Red River of the North (Fargo-Grand Forks corridor) and Missouri River system (Bismarck-Williston area) have extensive Zone AE designations. The 1997 Grand Forks flood caused $3.5 billion in damage. Fargo has invested billions in permanent flood diversion. NFIP requirements per 44 CFR 60.3 apply. Grand Forks and Fargo require significant freeboard above BFE for new construction.

Ground snow loads vary across North Dakota from 21 psf (Watford City area) to 50+ psf (northern counties). Structural design must account for snow per ASCE 7. Snow drift, sliding snow, and unbalanced loads are considerations.

North Dakota has deep frost penetration requiring foundations to extend 48-54+ inches below grade depending on location. Bismarck: 48", Fargo: 52", Valley City: 54". Climate Zones 6A and 7 are both "Very Cold" requiring significant frost protection.

Local floodplain ordinance compliance required for construction in FEMA-designated flood zones. Notable flood areas include Red River Valley (Fargo, Grand Forks), Missouri River corridor, and Devils Lake basin. Over 45% of NFIP claims in ND occur outside identified SFHAs. North Dakota State Water Commission provides floodplain management assistance.

The Badlands region and Little Missouri National Grassland in western North Dakota create WUI conditions. Theodore Roosevelt National Park and surrounding communities have experienced significant wildfires. Slope, McKenzie, and Billings counties have designated WUI areas. Grassland fires spread rapidly in high winds. IWUIC guidelines for ignition-resistant construction apply where locally adopted.