Windows Code Requirements in Alaska

Alaska is one of the most seismically active regions in the world. The 1964 Great Alaska Earthquake (M9.2) remains the second-largest earthquake ever recorded. Most of Alaska falls into Seismic Design Categories D, E, or F per ASCE 7. Anchorage and Southcentral: SDC E. Southeast: SDC D. Aleutians: SDC F.

Permafrost (permanently frozen ground) underlies significant portions of Alaska, particularly in Interior (Fairbanks area, Climate Zone 8) and Northern regions (North Slope, Climate Zone 9). Construction on permafrost requires special foundation design to prevent thawing and settlement. Discontinuous permafrost in Interior; continuous permafrost on North Slope.

Ice barrier underlayment REQUIRED statewide for all roofing projects (Climate Zones 6, 7, 8, 9) per IRC R905.1.2 and IRC Table R301.2(1) where IRC applies. Alaska designated as area with history of ice forming along eaves. Must extend minimum 24 inches inside exterior wall line. Steeper roofs (≥8:12) require 36" coverage measured along slope.

Alaska experiences extreme snow loads unmatched in the rest of the United States. Valdez area: 160+ psf ground snow load. Thompson Pass holds North American snowfall records. Anchorage minimum: 40 psf. Fairbanks: 60 psf. Southeast varies: 40-80 psf. Interior highlands: 80-120 psf. Snow loads are site-specific per ASCE 7.

Local floodplain ordinances apply in NFIP-participating communities. Alaska Division of Community and Regional Affairs administers NFIP. Many communities have riverine flooding (Fairbanks - Chena River), coastal flooding, and glacial outburst flood risks.

Alaska coastal communities face tsunami risk from local and distant earthquakes. 1964 Great Alaska Earthquake generated devastating tsunamis. Alaska Earthquake Center and NOAA maintain warning systems. Tsunami inundation maps available for many coastal communities.