What determines the best materials for cladding includes 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. Other materials are used in particular circumstances which includes copper, bronze, and titanium.
Steel and aluminum are the most popular cladding materials. They are used extensively in all of the three classifications of metal cladding types. Strength, durability, and cost of materials define the basic difference between steel and aluminum.
If steel cladding is used, they are normally pre-galvanized and pre-painted in coil form before panel manufacturing. 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 typical coating weight on cladding panels are 275g/m2 for zinc and 255g/m2 for zinc aluminum. IN polluted or coastal environment, the zinc aluminum alloy has better durability. The corrosion performance on premium pre-finished metals are improved. Then, the steel is coated with a variety of finishes for improved appearance and durability. The premium coating is a tough and durable coating. It is usually the case that difficult environmental conditions exist outside of the sheets. But, the underside of the sheet may be subjected to condensation and trapped moisture so it is normal to apply coating to this face at various specifications to suit both cost and environmental conditions.
Aluminum is known for its corrosion resistance. When bare aluminum reacts with oxygen, it results in a hard, dense layer that prevents 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.
It is difficult to compare the relative merits of steel and aluminum. Their advantages are seen in particular circumstances. Corrosion resistance is the greatest advantage of aluminum, but durability is the advantage of painted steel. While aluminum is lighter, steel is stronger so profiles have to be deeper or thicker to span the same distances between purlins.
Because of the greater amount of energy it requires to produce aluminum compared to steel, it make it more expensive. Steel is more impact-resistant and moves less than aluminum when subject to temperature changes. It performs better in fire because it has a higher melting point. Certain types of aluminum panels are formed more easily than steel because it has a low melting point.