Profiled metal wall cladding is available in a range of profiles, with the main ones being corrugated or trapezoidal. It is available in a variety of sheet lengths, widths and thicknesses, manufactured in aluminium alloy/zinc coated steel or galvanised steel with a factory-applied colour coating.
As a cladding, profiled metal can be installed horizontally and vertically. It is screw-fixed through the trough or crest to the framing. As metal is non-absorbent, it must be installed over an absorbent wall underlay.
The profile of the sheets creates significant voids behind the cladding and openings at sheet terminations. This allows for significant air entry and circulation, and for drainage to occur.
When installed horizontally, profiled metal cladding must always be fixed over a nominal 20 mm drained and vented cavity. This is because otherwise moisture that has leaked behind the cladding could be dammed at the point where the horizontal corrugations come into contact with the wall underlay. This moisture could pond and ultimately cause deterioration of the cladding and adjacent components.
The same problem may arise as a result of condensation moisture forming on the back of the sheet.
When installed vertically, corrugated profiled metal cladding can be direct-fixed on buildings with a risk score up to 20, as it provides good opportunity for gravity drainage and air circulation. (Trapezoidal profile can only be direct-fixed to risk score 6.)When installed vertically, profiled metal cladding can be direct-fixed on buildings with a risk score up to 20, as it provides good opportunity for gravity drainage and air circulation.
While generic details can be used as a basis for detailing things such as window and door penetrations and movement control joints, exterior detail design needs to be carried out by a competent and experienced designer. Profiled metal cladding is not a proprietary system, and there are a range of details that can be used for the same situation. It must be detailed comprehensively and accurately to ensure a weathertight performance.
Dark colours can be used. Although the cladding will expand and contract, the fixings and the laps of the sheets have the capacity to allow this to occur without damaging the cladding. While the factory-applied exterior finish is very durable, darker colours will fade. The exterior surface of the sheets also needs to be washed down regularly to avoid trapped contaminants causing surface deterioration.
Profiled metal cladding is considered to be a robust cladding system when detailed and installed accurately.
Profiled metal is vulnerable to:
- condensation damage
- junction details that can trap moisture
- poor detailing and installation.
Updated: 26 September 2018