Modular Steel-plate Composite (SC) construction reduces the construction time and labor requirement in their implementation for nuclear plants. For an effective structural design using SC wall panel, non-slender member is preferred for a faceplate of SC wall panel to satisfy the strength limit and the serviceability limit. The existing specifications developed for SC wall panel construction suggest width-to-thickness ratios (or faceplate slenderness ratios); however, these ratios differ in various specifications. This paper recommends the slenderness ratio of faceplates in SC wall panel. The results reveal that the faceplate slenderness ratio, the ratio of b/tp, should be less than or equal to 0.907 $$\sqrt {{E_s}/{F_y}} $$ E s / F y . In addition, the maximum stud (or tie) spacing will be a useful parameter to be considered during fabrication of SC wall, for structural design and also for field applications.