This layer supports the metal skin and its fasteners and is situated directly under the zinc roofing or cladding.
The support layer is important for building aspects such as:
- exposure to wind suction and wind uplift
- support the weight of the roofing
- exposure to external forces, for example snow loads
- physical building aspects; for example moisture effects
- fire protection requirements
The often used standing seam system is applied with a thickness of 0.7 mm or 0.8 mm. These coverings are not self-supporting and therefore a fully covered and rigid surface is required. The most popular solution is a built up by a substructure with rear ventilation. Another application is the non-ventilated design in several different forms.
The NedZink system can be used with a less complex substructure, it may be laid on a horizontal wooden lattices provided that their cross-section is no less than 25 mm x 35 mm, or on a lattice made of galvanized steel or aluminium. The distance between the centres should be 300 mm. The construction of the roof determines whether the lattice substructure is supported by wooden rafters or metal beams.