There are three principal forms of metal cladding used in constructions across Manchester, Rochdale, Bury, Bolton, Stockport and Oldham...
Profiled steel roofing sheets are used either to form a built-up roof cladding system, single-sheet metal roofing or the newer composite insulated wall and roof panels. And all three metal cladding systems (whether used for wall cladding or roof cladding) are classified on the basis of their method of manufacture and installation.
Profiled steel roof sheeting (a.k.a. 'corrugated roof sheets') were first made around 1840. They were instantly popular because they provided a simple-yet-secure roofing system. They were lightweight and easily stacked which also meant they could also be transported easily. The commonly-used generic name corrugated sheeting comes directly from the form the material takes during the manufacturing process.
In the early years during the 1800s - mainly due to their low cost - corrugated wall and roof sheets were often used for wall and roof cladding on agricultural and industrial buildings. However, since 1900, corrugated roof sheets have been used increasingly frequently in the construction of modern residential properties.
Steel or aluminium is normally used for the manufacture of this profiled metal sheeting. It can be used to create cladding and sheeting systems, single sheet systems or insulated composite-cladding panels. All three systems can be used for as roof or wall cladding. In each case the performance requirements vary.
This type of steel cladding consists of a metal liner, a layer of insulation material, a spacer system and an outer metal sheet, as illustrated below in Figure 1.
This system is built up from the constituent parts on site and provides a sturdy form of insulated roof cladding on any building. The use of the system is limited by the spanning capability of the metal cladding sheets, which is typically in the order of 2.0m to 2.5m depending on the applied loading. Built-up cladding systems must therefore be supported by secondary steelwork (purlins or side rails).
The Liner Sheet serves three purposes:
Liner sheets are usually manufactured from cold-formed, pre-coated steel or aluminium and possess a shallow trapezoidal profile. Steel cladding liners usually have a sheet thickness of 0.4mm or 0.7mm. Aluminium liner sheets are slightly thicker at 0.5mm or 0.9mm. The choice of liner will depend on the required spanning capability.
The metal cladding installation method and the acoustic requirements of the cladding will vary depending on whether it's used for wall cladding or roof cladding. Where required, the acoustic performance of the metal cladding (in particular its ability to absorb sound and minimise reverberation) can also be enhanced by the use of a perforated liner sheet.
The shallow liner sheets are not usually strong enough to walk on. So it's essential that the insulation, the spacer system and the weather sheet are all installed from boards or access platforms. However, the liner sheets do provide a non-fragile barrier against falling once they have been fully fastened. Where walking access is required it's common practice to replace the shallow liner profile with a more substantial sheet (i.e. a 32mm to 35mm trapezoidal profile in 0.7mm gauge steel).
The primary function of the insulation layer is to provide a barrier to the flow of heat between the interior of the building and the outside environment. The thickness of the insulation layer in many roof cladding and wall cladding installations has increased significantly in recent years - from approximately 80mm common in the 1980s up to 300mm in 2012 -as energy-efficiency building regulations have become more onerous.. It is not considered cost effective to go significantly thicker than this.
The most common form of insulation in built-up cladding systems is mineral wool quilt - due to its light-weight low-thermal conductivity, ease-of-handling and relatively low cost. Rigid mineral wool slabs are also available, although they are less 'deformable' than mineral wool quilts. This gives rise to the potential for air gaps occuring between the insulation and the corrugated roof sheets and corrugated wall sheets. Rigid mineral wool slabs are also much heavier than mineral wool quilts - which can increase the load on the supporting steelwork as well as making the manual handling of the material a little more difficult on site.
The primary function of this spacer system is to support the steel cladding weather sheet at the required distance from the metal cladding liner sheet. The components of the system must therefore possess sufficient strength and stiffness to transmit the required loading through to the purlins safely and without causing excessive deformation.
A common form of spacer is the bar-and-bracket system. The system consists of cold formed steel bars, which provide continuous support to the weather sheet, supported at intervals by steel brackets firmly attached to the purlins through the liner. Many bar-and-bracket systems also incorporate plastic pads which act as thermal breaks in order to minimise thermal bridging. Other types of spacer systems are also available, for example 'Z' spacers supported on thermally insulating plastic blocks.
The outer sheet of a double skin, built-up insulated roofing and wall cladding system is known as the 'weather sheet'. As the name suggests, its primary function is to protect the building from the exterior climate by forming a weather-tight envelope. However, the weather sheet should also be regarded as a structural element, as it plays an important role in transferring externally applied loads - whether from wind, snow or foot traffic - through to the other metal cladding components, secondary steelwork and the primary load-bearing frame.
The weather roofing sheets are usually made from either steel or aluminium and are available in a wide variety of finishes and colours. Steel weather roofing sheets are manufactured from pre-coated steel coil. Aluminium weather sheets are available in a milled finish or in a range of painted finishes.
A wide range of proprietary fasteners are available which can be made watertight. Most fasteners used for metal cladding applications are both self-tapping and self-drilling, although screws which are only self tapping are also available for use in pre-drilled holes. Fasteners can be used to connect cladding sheets to supporting steelwork (or other materials) or to connect adjacent cladding sheets.
For most fastener applications, a choice between plated carbon steel and stainless steel needs to be made.(typically grade 304 austenitic stainless steel is used). Visible fasteners have the option of factory-coloured plastic heads to suit the steel roofing sheets or the wall cladding. The use of corrugated metal roofing to form built-up insulated roof and wall cladding can be seen used on many industrial buildings throughout Manchester, Rochdale, Bury, Bolton, Stockport and Oldham.
Composite insulated roofing and wall cladding consist of a rigid layer of insulation sandwiched between two metal cladding skins. The result is a strong, stiff yet lightweight panel with good spanning capabilities - the latter due to composite action in bending. The insulated panels then span between the cold-formed purlins or side rails, which in turn span between the primary frame members. However, where the secondary steelwork is not needed for restraint purposes, it's quite common for composite insulated roof and wall cladding panels to span directly between the primary framing bars.
Standing seam and through fixed systems are available, with either a trapezoidal metal cladding sheet and shallow profiled liner, as shown above, or two flat / micro ribbed sheets. Profiled composite insulated panels are used for metal roof cladding to allow rainwater to run off without penetrating the fastener holes, while flat panels are favoured for metal wall cladding due to their better appearance. Any loads applied in the plane of the steel cladding (e.g. down-slope loads on a pitched roof) are transferred from the external cladding sheets through the two adhesive bonds, and the layer of insulation, to the internal sheet and the supporting structure.
Polyisocyanurate (PIR) is a common insulation material used in composite insulated panels . PIR expands rapidly when sprayed onto the metal cladding profile during production and bonds to it without the need for an adhesive. This property makes it ideally suited to the type of continuous manufacturing process employed by the larger manufacturers of foam-filled panels.
Alternatively, rigid slabs of mineral wool or other insulating materials, may be bonded to the insulated panel using an adhesive. This method is commonly used for flat-faced wall cladding. The use of composite insulated cladding sheets can be seen used on many industrial buildings throughout Manchester, Rochdale, Bury, Bolton, Stockport and Oldham.
Single-skin metal cladding is widely used in agricultural building and industrial building where no insulation is required. The metal sheeting is usually fixed directly to the purlins or side rails. The steel cladding is generally made from 0.7mm gauge pre-coated metal roof sheets and with a 32mm to 35mm trapezoidal profile depth. These steel roof sheets are generally used for both wall cladding and roof cladding. This is the most commonly used type of metal cladding in use with agricultural and industrial buildings throughout the Manchester area, Rochdale, Bury, Bolton, Stockport and Oldham.
Many buildings have been constructed using this type of metal cladding. However, as time passes they can require extensive renovation - especially once the lifespan of the original corrugated wall and roof sheets has been exceeded. The original metal cladding can deteriorate, or even fail altogether, and thus require extensive renovation or replacement.(Note: 'Over Cladding' is another technique used, where a new skin of steel cladding is placed over the original external fabric - either using metal roof sheets or metal wall sheets).
Why not call us now on 01706 352251 or 07792 248113 or email us to get the very best guaranteed price for your roofing or cladding project. Our helpful and expert staff based in Manchester will be delighted to hear from you!
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