Snow Loads on Sloped Roofs

Abstract

Snow slides off unobstructed slippery sloped roofs, but this behavior is not adequately quantified. As a result, most building codes and standards require slippery sloped roofs to be designed for excessively large snow loads, and dynamic forces imposed by snow sliding from slippery sloped roofs are approximated. We propose design recommendations using the results from a field investigation, wherein the effects of slope and thermal environment are measured independently of other snow accumulation factors. Data from instrumented sloped roofs are combined with observations from a group of similar structures. A flat‐roof building with four different thermal conditions is monitored as a control for the sloped roofs. Results are widely applicable since the field site has significant snow accumulation during the years of study. Regression analysis is used to formulate new sloped roof coefficients; the coefficient errors are normally distributed.