This study investigates the static stability of single-layer reticulated shells with and without roofing systems, offering a novel numerical modelling method. The analysis of more than 1000 numerical models has proceeded through three phases: analysis of shells without roofing systems, those with purlins, and those with full-roofing systems. In the case of shells with purlins or full-roofing systems, the MTC-Tie constraint in the Abaqus program was used to replace the purlin hangers connecting the shell H-shaped beams and purlins. This can efficiently reduce the number of elements and the error rates during the analysis. Furthermore, the roofing skin panels were attached to the purlins using Tie constraints. The static stability analysis was conducted, and the findings demonstrated that integrating purlins and roofing panels can significantly improve the static stability behaviour and the ultimate buckling capacity of single-layer reticulated shells with an approximate influence of 122% and 115%, respectively. The final influence for the full-roofing system was recorded at 137%. Moreover, equations for estimating buckling capacity and roofing purlin influence coefficients for single-layer reticulated shells were proposed by taking into consideration the shells’ different design parameters. Finally, the study highlighted the importance of considering stress distribution and buckling capacity differences between shells with and without roofing systems in the design.