Cladding is the process or result of applying one material over another. It is most often done to lend strength to or change the outward appearance of a surface. In construction, cladding often provides an additional layer of insulation as well and can increase the resistance of the surface to the water, sunlight, and other potentially damaging weather conditions.
The materials used for cladding vary widely. Wood, brick, metal, vinyl, aluminium, polystyrene, straw fibres, and other materials are all commonly used in producing cladding. The purpose of the cladding is usually the most important factor to determine the best material to use. Some are effective barriers to sound, some protect the under-layer from rain (but is not necessarily waterproof itself, merely redirecting the water from the interior layer), and others increase the beauty of the structure. Most cladding has more than one of these properties.
Cladding is often an important part of fire damage protection, but some cladding is highly flammable and can actually increase the danger of damage from fire. Likewise, some cladding can increase the noise of outside factors (such as rain or wind on a tin wall), while other types of cladding can create a sound barrier, either keeping loud noises inside a building (such as a production facility or music venue) or keeping outside noises out (such as in a recording studio or other building next to a busy road or airport).
Along with the material itself, the design that directs its installation will determine how effective it will be.
What is Cladding?
In the context of construction, ‘cladding’ is the material applied over an interior layer to provide a barrier against weather, sound, fire or temperature, or to change the appearance of the structure. Often more than one of these is desired. There is usually a gap between the cladding and the under layer, to allow rain to run down without touching the under-layer, or to provide a sound-insulating gap.
There are several facets of design to consider.
Cladding can be made of wood, brick, metal, vinyl, aluminium, polystyrene, straw fibres, or other materials. Often these materials are blended to allow more than one function to be fulfilled by a single layer of cladding. Materials can be vulnerable to fire or can increase the risk of fire damage, so this is a common and important consideration when deciding on the materials to use.
Purpose of the Cladding
Paramount in determining the materials to use, is the function you wish the cladding to provide. Rainscreen cladding, for example, is designed to protect against rain and wind, but also serves as a thermal insulation layer. Note that the rainscreen layer need not be waterproof in itself, as long as it blocks or redirects the water from the interior layer.
Single Skin Metal Panels are pre-formed from various metals and are probably the most common type of cladding. Any aluminium-clad building you see is using this type of cladding. It is very common in industrial and manufacture settings, as its light weight and easy coverage make it a cost-effective way to cover large buildings. It is durable and easy to install, so it keeps costs low and is excellent for low-maintenance buildings. It doesn’t normally have much thermal or sound insulating ability, but it is often combined with an intermediate layer of insulating material.
There is a specialised field of cladding that applies a layer to windows to create better insulation or protection. This obviously requires light to pass through the glass to various degrees and is a specialised field in the cladding industry.
Building Fire Vulnerability
There is often a cavity between the outer cladding and the inner layer, and in the case of a fire, this gap can act like a chimney or air vent, fanning the fire into greater intensity and pulling flames up through the interior of the wall. The effect is often a more rapid and intense spread of fire.
Some materials themselves can also be highly flammable, others much less so. Brick, fibre cement, steel and even reconstituted timber products are quite resistant to fire. Planks, plywood sheets and weatherboards, however, can catch fire or spread fire easily.
Composite cladding is itself made of more than one layer, typically consisting of 3-5mm of core material between two aluminium faces. Even panels that look the same may be comprised of different materials, and therefore have different properties and functions.