🕑 Reading time: 1 minute. Cladding is the process of layering one material over the other to protect a building from natural elements like wind and rain. It also provides insulation and noise control and boosts the aesthetic appeal of a building.
Cladding can be carried out on exterior walls as well as on interior walls. Criteria for Design of Cladding .
Criteria for Selection of Cladding Material . The design of cladding must take account of the following physical and statutory criteria:.
The cladding does not carry the weight of the building, but individual bays of cladding must carry their own weight.
They must also resist wind loads and impact, both external and internal. All these forces must be transmitted to the structural frame via suitable connections.
The connections between the cladding and frame must accommodate any dimensional ‘lack of fit’ between frame and cladding.
This is particularly important when a precisely manufactured cladding system is secured to a reinforced concrete frame, as the frame will be constructed to a lower standard of accuracy.
The design must also allow for movements: . In the frame – usually deflections, but also creep and long-term shrinkage of concrete.
In the cladding – usually induced by changes in temperature or moisture content.
The cladding is expected to restrict rainwater and snow. Waterproofing can be achieved in a variety of ways.
Cladding systems can generally be divided into three groups: . The material is largely impermeable, and joints are intended to be waterproof.
The material is largely impermeable, and the sheets or panels overlap so that water cannot penetrate.
Some amount of water penetrates the cladding material or the joints but is controlled within the cladding and channeled back to the exterior.
Types of Cladding Materials
Criteria for Selection of Cladding Material
The design of all heated buildings must include thermal insulation. In some systems, it is an integral part of the cladding construction.
In others, it may be incorporated in a separate inner lining or sandwiched between inner and outer layers.
In combination, weatherproofing, insulation, and lining must also prevent or control condensation. This may require vapor barriers and/or ventilation.
Specific levels of sound insulation may be required for buildings in noisy environments, such as near airports.
Heavy cladding systems possess inherently good noise attenuation. Lightweight systems can have their sound performance improved by internal linings.
Specific fire resistance periods are required for walls near boundaries and escape routes.
The Benefits of Wall Cladding
Fire barriers must be incorporated within voids where cladding passes compartment walls and floors and certain other areas.
In many cladding systems, the design criteria can only be met by the outer cladding acting in conjunction with internal linings or backup walls.
The design should also consider the availability of materials, manufacturing lead times, and speed of installation.
Types of Wall Cladding Materials
If a building is to be constructed quickly, the program will be partly dictated by the cladding system chosen.
With some systems, the building becomes considerably weatherproof on completion of an inner lining or backup wall, permitting internal services to operate simultaneously as the outer cladding is being installed.
4. Glass-Reinforced Cement (GRC)
The cladding materials are selected at an early stage in the development of the design to suit the architectural concept.
The normal criteria for the selection of cladding material are:.
To create a particular visual impression or aesthetic look of the building to complement the function of the building.
Wall Cladding Types
A limited budget will restrict the choice of materials or systems. Heavy cladding systems (generally masonry and precast concrete) may affect the cost of the frame.
Large panels may be impractical on congested sites or where there is no craneage.
Some materials are vulnerable to impact or vandalism. Designs may use lightweight cladding at a high level and plinth walls of brickwork or concrete to cope with ill-treatment at ground level.
Types of Exterior Wall Cladding Materials
When a cheap cladding system is proposed, savings in initial construction costs must be balanced against anticipated lifespan and likely maintenance requirements.
Masonry is one of the most common forms of cladding.
Exterior Wall Cladding
It is a strong, durable cladding, and a more expensive option of cladding that is employed in ‘high class’ work. It is widely used for low or medium-rise buildings.
Thin panels of natural stone have been used to clad both low and high-rise buildings.
Factors to be Considered for Wall Cladding
- The use of precast concrete panels to form the external envelopes of buildings became popular in the 1950s and ’60s.
- Panels were commonly used as load-bearing components within structural systems and were convenient for cheap, rapidly erected flats and offices.
- Current practice favors non-load-bearing panels in a more up-market role, taking advantage of their perceived solidity and ability to take both modern and traditional surface finishes.
- GRP is a light, resilient material that can be molded in various shapes.
- It is popular for streamlined, modernistic structures but can also be used to imitate traditional forms.
Advantages of using Cladding Systems
- The principal constituent materials are polyester resin and glass reinforcement.
- An outer ‘gel coat’ of resin may be used as a decorative coating.
- GRC cladding is manufactured by spraying a mixture of sand/cement mortar and alkali-resistant glass fibers onto a mold.
- It may be an intermediate between precast concrete and GRP in form and function.
- However, some installations have experienced problems of deterioration and deflections. Metal panels are often used on hi-tech style industrial or commercial buildings.
2. Precast Concrete
Many systems incorporate insulation between outer and inner skins, presenting a ‘finished’ appearance on each surface. Profiled cladding sheets are formed from pre-galvanized steel, aluminum, or fiber cement compositions.