Infill walls, also known as curtain walls, are filled with steel, timber or masonry materials and supported by load-bearing frames made from steel or concrete. They are constructed to support only the weight of the surrounding wall component and the wind load that acts upon it. Infill walls are typically set in between the beams and columns of the structural frame of a building. They are categorised as non-load bearing but can resist wind loads that are applied to building facades.
Timber infill walls are fairly lightweight, meaning they can be prefabricated in factories and transported directly to building sites. Timber infill walls also offer excellent insulation qualities, making them a popular choice in construction projects, especially in countries such as Sweden, where energy efficiency requirements in new buildings can be fairly strict. As well as the thermal insulation benefits, timber infill walls also offer an increase in available space on the interior of new buildings. This is due to the significantly reduced thickness of timber infill walls compared to buildings insulated with standard masonry work.
Light steel sections can be used as infill instead of timber. The thickness and size of the light steel can be adjusted to match the height of the building façade and to support the strength of the wind loads that act upon it. Steel can also be used in taller walls and walls with larger openings than timber as it is significantly stronger. Light steel is also used for separating walls in building interiors where dual layers are usually used to ensure fire safety and acoustic separation.
Walls filled with concrete blocks or clay bricks were the traditional means of wall construction, However, using masonry components has become less popular as it requires sustained periods of material handling, which can increase labour costs and slow down construction. Masonry infill walls by large windows also require additional strengthening beams to resist the force of the strong wind forces that can occur in these areas.
Concrete infill walls typically come as large premade panels big enough to cover a single building storey. The panels can be supported from the bottom or top hung. Once position in place onto the floor slab beneath, the concrete panels are secured to the level below or above using bolts. An average concrete panel weighs around 300kg (47.25 stone) and measures about four metres (13.1 feet) in height.