Sitka's Structural Design Criteria

(For use with the International Building Code 2021 or the American Society of Civil Engineers - Minimum Design Loads for Buildings and Other Structures ASCE 7-16.)

  • Wind Load:
    Basic wind speed, V (3-second gust wind speed) = 150 miles per hour
  • Snow Load:
    Ground snow load, pg = 50 pounds per square foot
  • Earthquake Load:
    Maximum considered earthquake ground motion-
    0.2 second spectral response, Ss = 0.97 g
    1.0 second spectral response, S1 = 0.60 g
  • Frost Depth:
    Minimum of 18 inches required from finish grade to base of footing or base of non-frost susceptible fill.
  • Wind Exposure Definitions

Codes in effect in Sitka:

Residential (adopted by Sitka General Code):

  • 2021 International Residential Code (not including plumbing and electrical)
  • 2021 Uniform Plumbing Code
  • 2020 National Electrical Code

Commercial (adopted by State statute and Sitka General Code)

  • 2021 International Building, Fire, and Mechanical Codes
  • 2021 Uniform Plumbing Code
  • 2020 National Electrical Code
  • 2021 International Existing Building Code