Before diving into the specifics of the 200x73x77x20mm Galvanized Z-Purlin, let’s clarify what a Z-Purlin is. Purlins are horizontal beams that support roofing and siding. The “Z” shape refers to the cross-sectional profile that resembles the letter Z, which provides additional strength and support. These purlins are essential in constructing steel-framed buildings, warehouses, and agricultural structures.