This research reports a numerical study on the flexural strength of single-lipped Zed-Purlin sections under two equal moments applied at the ends of the specimen. The effects of attaching corrugated steel sheeting to the tension flange of Z-purlins on the structural behavior are investigated. The studied parameters of the specimens are: types of corrugated steel sheeting, depth-to-thickness ratio, and the span of the purlins. Linear and non-linear analyses using finite element software are conducted. Results show that a tension flange braced by corrugated steel sheeting can increase the section capacity of Z-purlins and change the failure mode. The results of the ultimate moment obtained from finite element analysis have been compared to both the nominal flexural strength according to the Egyptian code (ECP) and the North American Specifications (AISI). The results of purlins with sheeting determined by ECP are conservative due to ignoring the effect of corrugated steel sheeting on capacity, while the results from AISI are in good agreement with finite element analysis as they take into account the effect of sheeting.