The advantages of installing a ventilated wall include increased energy efficiency and extended lifetime of the facade. In warm weather, ventilation is necessary to prevent the cladding – and subsequently the building – from overheating, while in colder, damper weather it will stop the build-up of moisture and condensation.
Inlet / outlet principle
Cedral facades are installed using the ventilated rainscreen system. A cavity is created between the wall insulation or substructure and the cladding, allowing air to flow in at the base and out at the top. This ‘chimney effect’ helps to maintain an ambient air temperature year-round, effectively protecting against moisture.
To provide an effective ventilation cavity behind the facade this space must be provided with adequate inlets and outlets. For most structures, Cedral recommend a minimum 30mm continuous gap between the cladding and the building fabric and a minimum 10mm continuous gap at openings.
Tips to remember when installing a ventilated rainscreen cladding system
It will be important to plan where vents, extractor ducts and surface cables will pass through the insulation, the cavity and out through a precise point in the cladding. This involves sealing the cavity and integrating perforated ventilation closures above and below the penetration points. It’s essential to keep the continuous airflow while maintaining the weather-tightness, insulation integrity and prevent pests from entering.
When specifying the closure make sure you calculate how this will affect the effective airflow behind the facade to stay within the manufacturer’s recommendations.
Mind the air gap – We sometimes see the vital space at the base being reduced, blocking the ventilation. At higher levels, take care with sealants to close off air gaps under windows and soffits. When using membranes, ensure they are installed in a way that will not restrict airflow.
At Cedral we have a dedicated technical support team to help with topics such as ventilation. Cedral’s latest RIBA accredited CPD presentation “Ventilated Fibre Cement Rainscreen Cladding: Design Principles and Project Integration” has been designed to give architects practical guidance and design inspiration.
