Infill panel walls
Infill panel walls are a form of cladding built between the structural members of a building. The structural frame provides support for the cladding system, and the cladding provides separation of the internal and external environments. Infill walling is different to other forms of cladding panel in that it is fixed between framing members rather than being attached to the outside of the frame.
Infill panel walls are not considered to be load bearing, although they are required to resist wind loads applied to the façade, as well as supporting their own weight. Other functional requirements for infill panel walls include:
- They are welf-supporting between structural framing members.
- They provide weather-resistance.
- They provide thermal and sound insulation.
- The provide fire resistance.
- They provide sufficient openings for natural ventilation and glazing.
- They can accommodate differential movements between themselves and the frame.
 Types of infill panel walls
Traditionally, infill panel walls used brick/masonry or timber; however, these are more time consuming than modern alternatives and have been largely replaced by lightweight steel C-sections that span between floors and around openings.
These can be constructed from clay bricks or concrete blocks, in a solid or cavity form. The same principles of solid and cavity wall construction apply to infill panel walls. They can be tied to columns using wall ties cast at 300 mm centres, or located in anchor slots.
These are usually large precast concrete panels that are the height of one storey and of a width dictated by the spacing of the frame. They can be either top-hung or bottom-supported. Panels that are integral may be clad in other materials, most typically stone.
The maximum panel size is generally restricted by the transport considerations and crane lifting capacity.
Multi-storey framed construction often uses lightweight steel for infill panel walls that support the external cladding. The panels are fixed between the structural horizontal and vertical members of the frame, and can incorporate architectural features such as large windows, parapets, and so on. The panels are lightweight, and are quick and easy to instal.
The size and thickness of the steel sections can be varied according to the façade wall height and windloads. Typically, C-sections and U-sections of 75-100 mm depth are cold roll-formed from galvanized steel strip of 1.2-3.2 mm thickness. Pairs of C-sections may be used next to large openings, and are typically placed at 400 or 600 mm spacings.
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