... made of steel Q235B, pillars are made of square tube or double C section steel, purlin is made of section steelRoof, exterior ... and all the installation fittings included.PVC windows or aluminum window: 4mm single or double glass, sliding windows with fly screen ... 40x40x2.5mmStep board is made of 3mm steel boardPillar is “L” section steel 36x3Assembly material:Nails, glue, bolts, polyurethane, edge ...