The substructure transmits the load of the cladding itself and the wind load to the enclosing external wall. Metal substructures are generally used as these can compensate for tolerances in the shell construction. Most systems consist of a two-part construction, which is fastened to the supporting external wall using anchors. This base construction is aligned plumb and flush and acts as a support for installing a variety of facade cladding materials.
The substructure system must be designed in such a way that materials used can expand due to temperature changes without creating stresses in the structure.
For example, when using aluminium profiles with a length of approx. 3 m, an expansion of 5mm must be taken into account (temperature range -20° C to 80° C).
So-called fix point / sliding point structures are often used for this purpose.
The bracket used has the following functions::
- acts as a fix point for screwing the profiles into position in the round hole – the profile is fixed, transmission of own weight and wind loads
- acts as a sliding point for screwing the profiles into position in the slot hole – the profile slides in the slot holes, transmission of wind loads only