The way that materials for cladding are chosen is their cost, manufacturing parameters, durability, and appearance.
Steel and aluminum are the most common materials used for cladding. It also includes stainless steel and weathering steels. Copper, bronze, and titanium are used for cladding in particular circumstances.
The most popular cladding materials are steel and aluminum. In the classifications of metal cladding types, these two are extensively used. The basic difference between steel and aluminum lie in their strength, durability and cost of each material.
Before panel manufacturing steel cladding, they are first pre-galvanized and pre-painted in coil form. When steel is galvanized it produces a hard, durable outer layer since it is first dipped in molten zinc or zinc aluminum alloy, then bonded with metallic coating. The thickness of galvanized steel varies and this is expressed as the weight of zinc or zinc aluminum per square meter on both sides of the sheet. The minimum coating weight on cladding panels is typically 275g per square meter for zinc and 255 g per square meter for zinc aluminum. Zinc aluminum alloy has better durability in polluted or coastal areas. The corrosion performance on premium pre-finished metals are improved. In order to improve appearance and durability the steel is coated with a variety of finishes. With premium coating, you get a tough and durable steel panel. Outside of the sheet they may be difficult environmental conditions that exist. When condensation and trapped moisture is found in the underside of the sheet, they apply coating to its face in order to suit the environmental conditions and cost.
Aluminum is resistant to corrosion. Bare aluminum reacts rapidly with oxygen to form a hard, dense layer that inhibits further corrosion. Cladding aluminum is generally in the form of an allow with magnesium and manganese. Aluminum has sufficient durability on its own but it can be improved by adding an organic or metallic coating.
You cannot compare easily the merits of steel and aluminum. Their advantages are seen in particular circumstances. Aluminum is inherently more corrosion resistant than steel, but painted steel is durable. Though aluminum is lighter, it is not stronger than steel so it needs deeper or thicker profiles to span the same distance between purlins.
Because of the greater amount of energy it requires to produce aluminum compared to steel, it make it more expensive. When there are temperature changes steel is more resistant to impact and moves less than aluminum. The melting point of steel is higher so it performs better in fire. Certain types of aluminum panels are formed more easily than steel because it has a low melting point.