An air barrier system is a system within the building enclosure installed to prevent the uncontrolled flow of air into and out of the building envelope.As a membrane within a building’s wall or structure, an air barrier has the effect of resisting the passage of moisture from the internal, warm side of the wall. Air barriers are intelligent vapour control layers. Like a vapour control layer, an air barrier prevents moisture from inside the building from entering the wall and insulation.
If water vapour infiltrates the insulation and builds up, it will trap and create interstitial condensation. This will effectively rot the fabric of the wall and create an unhealthy environment. An air barrier will hold moisture until ambient changes cause the moisture to rise away from the insulation layer.
Air is capable of holding a high level of moisture in the form of vapour. When vapour-laden air moves from one location to another, it carries the vapour with it. Installing an air barrier will control the flow of air and, by extension, the flow of moisture.
Effective management of moisture requires the control of both air movement and moisture flow as the two are always intertwined. This can be achieved with ITP’s advanced air barrier membranes.
Our air barriers not only improve energy-efficiency, but also provide excellent moisture regulation. An air barrier provides an effective solution wherever air can flow within a wall, roof or floor structure.
Misunderstandings surrounding “vapour barriers” and “air barriers” often lead to their incorrect application; their basic function is the control of air and vapour, but the two have different methods of dealing with these potentially destructive issues.The vapor barrier prevents vapor diffusion (the process of moisture passing through breathable building materials) whereas an air barrier prevents air leakage through differences in air pressure between the interior and exterior.
Both of these processes prevent moisture from reaching the dewpoint in a wall – in other words, the point where a fall in temperature causes air to contract, and water vapor turns to liquid. Since warmer air is capable of carrying more moisture, the dewpoint is determined by the level of moisture in the air and the difference in temperature from inside to outside.
Although vapour barriers and air barriers have a different method of managing the air and vapour, the result is the same: the protection of the insulation and wall structure from interstitial condensation.
ITP manufacture two advanced air barrier membranes:
POWERLON® Air Barrier
POWERLON® Air Barrier is a coated, non-woven material with an air-proof and waterproof finish to provide the building envelope with an effective encapsulation.
POWERLON® VariPerm is an innovative, intelligent ‘self-adjusting’ air barrier which reacts to changing temperature and humidity by automatically increasing or decreasing the membrane’s permeability to water vapour. Air Barriers ensure that the building envelope is property sealed to control ventilation and prevent heat loss in compliance with Building Regulations Part L. Installed on the warm side of insulation, AVCLs protect insulates from interstitial condensation.