Last edited 02 Nov 2016

Cladding for buildings

Contents

[edit] Introduction

Cladding is the visible external finish of a building, such as the roof or external walls.

Cladding is often pre-fabricated in panels that are attached to the structural frame of the building, and cladding systems can be purchased 'off the shelf'. Some definitions suggest that cladding is a non-structural external finish, as opposed to a load-bearing external construction. However, cladding can play a structural role transferring wind loads, impact loads and self-weight back to the structural framework. In particular, wind causes positive and negative pressure on the surface of buildings and so cladding must be designed to have adequate strength and stiffness to resist this load, both in terms of the type of cladding selected and its connections back to the structure.

Cladding is needed to:

  • Create a controlled internal environment.
  • Protect the building from external conditions.
  • Provide privacy.
  • Prevent the transmission of sound.
  • Provide thermal insulation.
  • Create an external facade.
  • Prevent the spread of fire.
  • Generate an 'airtight' building envelope.
  • Providing openings for access, daylight and ventilation.

Cladding systems may include components, such as windows, doors, gutters, roof lights, vents and so on.

The nature of cladding selected for a particular building will depend on how the building is going to be used, internal and external conditions, aesthetic requirements and so on. The use of a high-quality, well designed building cladding can maximise thermal performance, minimise air leakage, and optimise natural daylighting. This can help reduce the need for mechanical and electrical building services, and so improve energy efficiency and lower capital and running costs.

The appearance of a building is also an important factor when selecting and designing building cladding and is an important aspect of the design considered by local planning authorities.

When selecting a suitable cladding, designers might consider issues such as:

Poor design detailing or installation may compromise cladding performance and can even lead to cladding collapsing or cladding panels being pulled away from the structure.

[edit] Types of cladding

Types of cladding include:

Some of the more popular types been described below.

[edit] Curtain walling

Curtain wall systems are a non-structural cladding systems 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.

[edit] 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. Western red cedar is generally sourced from North America (predominantly Canada), but it is starting to be grown in the UK. Other softwoods that are often used include Douglas fir and Scottish and Scandinavian larch.

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. Hardwood cladding also requires pre-drilling which can add to installation time and costs.

Thermally modified timbers are also being used such as Kebony, Keywood, Platowood and ThermoWood. The softwoods are heated to high temperatures which removes the moisture and resins, resulting in a stable and durable material.

[edit] 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.

[edit] PVCu

One of the cheaper forms of cladding is PVCu with white being the cheapest option. It often has less detailing than timber and requires less maintenance, although it can discolour.

[edit] Tile hanging

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

[edit] Render

Rendering can be undertaken by hand or spraying and is applied in a similar way to plaster in layers. It can be textured, patterned or left smooth.

[edit] 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.

[edit] Find out more

[edit] Related articles on Designing Buildings Wiki

[edit] External references