Noise and wind load
Metal roofi ng can produce excessive noise in the event of extreme hail or heavy rain. Applying a separation layer for sound insulation can diminish these effects. The separation layer ensures a reduction of 8 dB and can be supplied in different widths.
The requirements for the wind loads that a Dutch building construction must meet are described in the NEN standards of the Dutch Standardization Institute (NEN). The research organisation, TNO has derived calculation rules from these norms for zinc roof systems. They concern rules for establishing the wind load as well as methods for deducing the strength.
For a fully supported structure, such as the traditional standing seam, roll cap or shingle roof, one mainly has to counter any wind suction that occurs. For self-supporting constructions, wind pressure, the structure’s own weight and consequently the deflection of the material play a role. In addition, the fixation method as well as the profiling (system option) of the material is important. The wind suction affecting a façade or roof section depends on the shape and dimensions of the building, the slope of the roof and the location of the roof covering.
Wind suction means uniformly distributed wind suction caused by wind and is measured in Newtons per m², perpendicular to a surface facing down from the wind. The calculation of wind suction, depending on the altitude and the differences between the wind areas in the Netherlands is registered in a NEN norm.
Zinc roof coverings and wall claddings are attached to the substructure by means of clips. The clips of the standing seam and roll cap system are located on the longitudinal seam between the bays. The clips of the lozenge system are locked in the folded edges of each lozenge. For fl at roofs with soldered sheet coverings the clips are placed underneath the soldered joint. The clips are often made of titanium zinc, but can also be made from stainless steel, galvanised steel or aluminum. Roof and wall coverings that consist of bays mainly are attached with fixed and sliding clips.