Types of cladding index

In general the term cladding refers to a covering or coating on a structure or material, the application of one material over another to provide a skin or layer, for protection. More specifically cladding will usually refers to components that are attached to the primary structure of a building to form non-structural, external surfaces, as opposed to buildings in which the external surfaces are formed by structural elements. Cladding most commonly refers to horizontal elements of a buildings fabric but can also refer to elements such roof cladding (usually roof covering), interior cladding and possibly even floor cladding (usually called just flooring).

Applied surfaces such as directly applied render, which add some structural capability to a structure are not normally referred to as cladding, but might be. For example structural blockwork that then receives first a layer of rigid insulation which is then finished in a render, the combination of which might be referred to as cladding, or sometimes over-cladding, where it is added later as part of a retrofit solution.

There are a wide variety of cladding types, associated elements and different terms to describe explain these, some of which can be confusing and misleading. At the same time cladding as a term, its uses and understanding of it have also come under increasing scrutiny since the devastating fire at Grenfell tower in 2017, in which 72 people lost ther lives. In this case a particular cladding solution was employed which contributed to the severity of fire in a way that the Grenfell fire inquiry deemed to have been fully and wholly avoidable. As such cladding materials, types, design and specifications have been continually in the spotlight since, especially safety concerns surrounding the same and other cladding materials that have historically been used on a large number of other high-rise buildings.

Since the Grenfell tragedy the UK Government set up the Building Safety Fund for the remediation of non-ACM Cladding Systems (England only) Registration prospectus, published by MHCLG in May 2020. This document refers to cladding systems and suggests that: 'A cladding system includes the components that are attached to the primary structure of a building to form a non-structural external surface. The cladding system includes the weather-exposed outer layer or ‘screen, fillers. Insulation, membranes, brackets, cavity barriers, flashing, fixings, gaskets and sealants.'

Designing Buildings has many articles relating to the term cladding, which are referred to here.

Types of cladding

The NBS Building libraries categorise types of claddings and coverings as:

H10 Patent glazing

H11 Curtain walling

H13 Structural glass assemblies

H14 Precast concrete and glass lens / paver rooflights / floorlights / pavement lights / security panels

H20 Rigid sheet cladding

H21 Timber weatherboarding

H22 Plastics weatherboarding

H30 Fibre cement profiled sheet cladding / covering

H31 Metal profiled / flat sheet cladding / covering

H32 Plastics profiled sheet cladding / covering

H40 Glass fibre reinforced concrete panel cladding / components

H41 Glass fibre reinforced plastics cladding / features

H42 Precast concrete panel cladding / features

H43 Metal composite panel cladding / features

H51 Natural stone slab cladding / lining / features

H60 Plain roof tiling

H61 Fibre cement slating

H62 Natural slating

H64 Wood shingle and shake roofing

H65 Single lap roof tiling

H67 Metal single lap roof tiling

H71 Lead sheet coverings / flashings

H72 Aluminium strip / sheet coverings / flashings

H73 Copper strip / sheet coverings / flashings

H74 Zinc strip / sheet coverings / flashings

H75 Stainless steel strip / sheet coverings / flashings

H90 Tensile fabric coverings

H91 Thatch roofing

H92 Rainscreen cladding

11 of the more common types of cladding are described below.

Curtain walling

Curtain wall systems are a non-structural cladding system for the external walls of buildings. They are generally associated with large, multi-storey buildings. Typically curtain wall systems comprise a lightweight aluminium frame onto which glazed or opaque infill panels can be fixed. These infill panels are often described as 'glazing' whether or not they are made of glass.

See Curtain wall systems for more information.

Sandwich panels

Sandwich panels (sometimes referred to as composite panels or structural insulating panels (SIP)) consist of two layers of a rigid material bonded to either side of a lightweight core, so that the three components act as a composite.

See Sandwich panel and Metal composite panels for more information.

Patent glazing

The term ‘patent glazing’ refers to a non-load bearing, two-edge support cladding system. Patent glazing bars provide continuous support along two edges of glazing infill panels (rather than four-edge curtain walling), and are fixed back to the main structure of the building. This system supports its own weight, and provides resistance to wind and snow loading, but does not contribute to the stability of the primary structure of the building.

See Patent glazing for more information.

Rainscreen

A rainscreen (sometimes referred to as a ‘drained and ventilated’ or ‘pressure-equalised’ façade) is part of a double-wall construction. The rainscreen itself simply prevents significant amounts of water from penetrating into the wall construction. Thermal insulation, airtightness and structural stability are provided by the second, inner part of the wall construction.

See Rainscreen for more information.

Timber cladding

One of the most popular methods of cladding is through the use of timber softwoods, such as western red cedar. This type of wood is relatively knot-free and has a natural resistance to decay and moisture. It can be readily stained or painted and altered to create a range of profiles.

Hardwoods can also be used including oak and sweet chestnut. Both of which contain high tannin levels which can result in leaching and streaking after exposure to the elements. Thermally modified timbers are also being used such as Kebony, Keywood, Platowood and ThermoWood. These softwoods are heated to high temperatures which removes moisture and resins, resulting in a stable and durable material.

See Timber cladding for more information.

Metal profile cladding

Sheets are manufactured in a range of corrugated and other profiles, such as trapezoidal, sinusoidal or half-round. The profiles are manufactured from sheets fed through banks of forming rollers.

See Metal profile cladding for more information.

Tensile fabric coverings

A fabric membrane is 'stretched' to form a three-dimensional surface that may be used to create a roof, shading, or decorative component. Sometimes described as 'modern tents', fabric structures use very little material compared to other forms of construction, and are typically translucent, but they provide little thermal mass or insulation and can have a shorter lifespan than some materials.

See Fabric structures for more information.

Brick slips

Brick slips are thin layers of masonry and are of similar appearance to conventional bricks. They are available in a variety of styles and colours.

See Bricks for more information.

Tile hanging

The traditional method of cladding a property is through the use of tiles. The addition of which can add character to older properties.

Shakes and shingle

Shakes and shingles are produced from split logs and look similar to timber tiles. Shakes are typically split from the log using a chisel and mallet whilst shingles are sawn off.

For more information, see Shingle roofing.

uPVC

One of the cheaper forms of cladding is uPVC with white being the cheapest option. It can have fewer detailing requirements than timber and requires less maintenance, although it can discolour with age.

For more information, see uPVC weatherboarding and Plastic cladding.