subject: The Specification Of Roof And Wall Cladding [print this page] Performance requirements Performance requirements
The specification of roof and wall cladding has implications well beyond the aesthetics and weathertightness of the buildings performance, from its construction right through to it's eventual demolition and disposal. Sufficient care must be taken when specifying the cladding to insure the fitness for purpose of the whole building is not compromised.
Specifying profiled metal cladding
The following factors should be taken into consideration when specifying profiled metal cladding systems:
* Weathertightness
* Strength and rigidity
* Thermal insulation
* Control of thermal movement
* Sound insulation
* Fire resistance
* Appearance
* Durability
* Cost
* Daylighting
* External attachments
* Lightning protection
* Design detailing
* Maintenance, remedial work and renewal.
* Control of air leakage
Weathertightness
The primary function of the cladding is to provide a weathertight building envelope, suitable for the intended use of the building. With this in mind the specifier must give careful consideration to the design of the building, location of the building, design and construction of side/end laps and orientation to the external climate.
In general roofs are at a greater risk of leakage than walls and the risk increases as roof pitch decreases.
Strength and rigidity
The profiled cladding system serves as an important structural element. They are required to carry externally applied loads, such as snow and wind loading without deflecting excessively or compromising the other performance requirements. In addition, the cladding is often required to provide restraint to the purlins and side rails.
Appearance
Roof and wall cladding choice will have a significant impact on the appearance of a building. The following factors are particularly important:
Profile shape
The shape of the profile will have an impact on the appearance due to its effect on the perceived colour and texture of the cladding (caused by the reflection of the light).
Colour
The profiled cladding sheet is available in a wide range of pre-finsihed colours and textures.
Fasteners
The overall appearance of the building can be affected by the choice of fasteners especially on wall cladding or steeply pitched roofs. Cladding specifiers should, therefore, give careful consideration to the size, shape, colour and locations of the fastener and washers.
