Snow Load and Pergola Engineering in Boise

Boise City Code 9-1B-33 sets a 20 psf ground snow load, a minimum roof snow load of 25 psf and a 90 mph design wind speed. The Boise area's normal annual snowfall is 17.6 inches (NWS, 1991-2020), and some years bring far more. The city treats most freestanding pergolas over 200 square feet as pole construction designed by an Idaho licensed engineer. See structural engineering and permitting and the Boise page for the sources.