In this post, I will provide a brief overview of calculating flat roof snow loads that are specified in ASCE 7-10, Chapter 7. Before diving deeper, it’s a good idea to review the definitions of parameters used in the snow load formula.
Is = Importance Factor, ASCE 7-10 Table 1.5-2
pg = Ground Snow Load, ASCE 7-10 Figure 7-1 and Table 7-1
Flat Roof Snow Load Formula, ASCE 7-10, Equation 7.3-1
pf = 0.7CeCtIspg
Flat Roof Snow Load = 0.7 times the exposure factor times the thermal factor times the importance factor times the ground snow load