What are the common sheeting and cladding systems used in the UK?
- Read time: 3 minutes
- Date: 24 Jun 2021
- Sheeting & Cladding
The system selected will depend on the design of the building, application, material and other factors such as the environment, forces on the structure (loading) and thermal requirements. The build-ups of the different systems will affect your choice of fixing system and the fasteners used.
Common sheeting and cladding systems include:
1. Single skin system
A single skin system features an uninsulated sheet of metal, which is profiled to give it additional strength. The sheet is fixed directly onto the purlins.
2. Twin skin system
A twin skin system (also known as a built-up system) features two sheets of profiled metal held apart using a spacer system, creating a cavity for the insulation. The build-up includes:
The weather sheet or outer sheet, which creates the weather tight envelope.
Mineral wool insulation, which is installed on top of the liner sheet
VCL (Vapour Control Layer), to prevent moisture vapour penetrating the cavity
The spacer system, which supports the weather sheet and transfers the load to the purlin
The liner sheet, which provides an airtight layer and supports the insulation
What fasteners should be used for a twin skin system?
Self-drilling fasteners are used to secure the system together. There are two types of fasteners used on twin skin systems:
Primary fasteners are structural components and are designed to transfer loading from the roof or walls to the structural elements of the building. They are normally positioned in the valley of the profile. The exact fixing pattern should be determined as part of the design process. Primary fasteners should be specified in accordance with the design of the building, forces it will need to withstand and environmental factors.
Secondary fasteners are non-structural components used to join sheet to sheet or flashing to sheet. They must be positioned correctly in relation to the seal. The drill point, thread, diameter and length will vary according to the application.
In what applications are twin skin systems used?
Twin skin systems are suitable for both roof and wall applications. It can be used in roofing down to a 4° pitch. This type of system is often used on walls to enhance the look of a building as the outer profiled sheet can be positioned either vertically or horizontally.
3. Standing seam system
Standing seam systems are similar to twin skin systems, but the outer weather sheets lock together over a clip or halter to form a standing seam. This hides the fixings, protecting them from the elements and reducing the risk of leaks.
What fasteners should be used for a standing seam system?
The main type of fixings are:
Primary fasteners are structural components and are designed to transfer loading from the roof or walls to the structural elements of the building. They are used to attach the liner sheet to the purlins and to attach the clips or halters to the liner. The exact fixing pattern should be determined as part of the design process. Primary fasteners should be specified in accordance with the design of the building, forces it will need to withstand and environmental factors.
Secondary fasteners are non-structural components used to join sheet to sheet or flashing to sheet.
The fixing pattern for clips is critical and should be considered during the design phase. Fixed points are needed to prevent creep down the slope.
In what applications are standing seam systems used?
Standing seam systems are suitable for both wall and roofing applications. Because the fasteners are not exposed, standing seam systems can be used on roofing systems with very low slopes or pitches. They can be curved or tapered and are therefore often used for projects with unusual designs.
4. Composite panel system
Composite panels, also known as insulated or sandwich panels, can be used on walls and roofs. Composite panels feature two metal skins (the liner and the weather sheets), which are bonded to an insulation material during manufacture.
What fasteners should be used for composite panels?
On most applications, fasteners are fixed through the valley (the lowest part of the profile) to the purlin. In some cases manufacturers may recommend crown fixing using a saddle washer.
Some composite panels used for walls have a concealed fixing system, where the fasteners are installed in the panel joint, to create a clean line across the building and to give added security because fixings can’t be tampered with.
Self-drilling fasteners are used to secure the system. There are two types of fasteners used on composite panel systems:
Primary fasteners are structural components and are designed to transfer loading from the roof or walls to the structural elements of the building. A specially designed composite panel fastener should be used as the primary fastener to attach the panel to the building. The exact fixing pattern should be determined as part of the design process. Primary fasteners should be specified in accordance with the design of the building, forces it will need to withstand and environmental factors.
Secondary fasteners are non-structural components used to join sheet to sheet or flashing to sheet. They must be positioned correctly in relation to the seal. The drill point, thread, diameter and length will vary according to the application.
Which types of composite panel systems suit which applications?
There are a variety of different composite panels, and the type used depends on the application.
Composite panel systems are suitable for both roof and wall applications. Flat or micro rib panels are popular for wall applications with their concealed fasteners creating a smooth finish. This type of wall system can be positioned either vertically or horizontally.
Composite panels may also be used in conjunction with other cladding systems such as tiles, brick slips or rainscreen façades.
