Codes & Design Requirements

The Building Codes listed below are effective as of April 9, 2015.  The codes have been adopted and amended by the Administrative Rules of Montana (ARM) Title 24, Chapter 301, and adopted by the City of Helena in Title 3 of the City Code.

Design Requirements

  • Seismic Design Category according to the 2012 International Building Code (IBC), typically D0 or as calculated by International Building Code, Chapter 16 based on site specific soil conditions.
  • Wind Load - f 3s - 90 mph, f fm - 75 mph
  • Snow Load - (ground/roof) 30 lbs psf minimum
  • Frost Depth - 42" minimum to bottom of footing
  • Ice and Water Barrier Under-layment Required – Yes