Material selection
The selection of paneling materials depends upon the building's intended use, the environment conditions as well as the applicable specifications (structural, static, thermal, sound proofing, fire resistance etc.) dictated by local and international codes.

Metallic sheets
In addition to the form, mechanical properties and material thickness play a significant role in the durability of the formed sheets. The factors affectinq the selection of individual materials (steel, aluminum, copper, plastics etc.) are mechanical strength, malleability, deflection, weight, resistance to corrosion as well as technical-economic factors. Steel's resilience rate, for instance, is triple that of aluminum, but it is also three times heavier than the latter. The finish of the sheet (i.e., its protective surface cladding) is another important factor.

The base material is standard hot-dip galvanized sheet steel; with the option of color coating with Poiyester, Silicon Polyester, Acrylic, PVC and PVDF paint; its technical specifications are included in the table.

Form
Cladding sheet profiles are selected so that the following two criteria are met:

• The first is sheet bearing capacity, which determines the profile's capability to be used in various openings.
• The second is rainwater drainage capacity, the material having a gutter depth sufficient to eliminate any hazard of trapezoid flooding with rainwater.

Loads
No national or international regulations exist in this area yet; nevertheless, in practice several widely recognized design codes are used (such as DIN Eurocodes, BS, EN etc.). A comparison of such codes in terms of sheet strength in a normal loading range will reveal results with only minor discrepancies.

Snow and wind loads, spot loads (weight of a worker), failure types under loads exceeding the rupture limit, deflection rates and peak loads, are strength requirements described in the codes which comprise the basis for the preparation of permitted load / opening tables.

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