Condensation is defined as the process where water in the air transforms into liquid water when warm air comes into contact with a cold surface below the “dew point”. The dew point is a temperature which varies depending on the temperature and humidity of the warm air. A simple demonstration of this is the water droplets that form on the surface of a bottle of a cold drink on a hot day. The hot air hits the surface of the bottle which may be at around 6°C and the water in the air condensates on the bottle.

Controlling Condensation
Where condensation forms in your home

In an energy efficient airtight building with a conditioned internal environment, moisture is added to the air by the occupants who are showering, cooking and breathing (exhaled air has a relative humidity of 100%). This creates an internal environment with a higher vapour pressure than the outside environment which forces or ‘drives’ the water vapour in the air outward in every direction looking for equilibrium. 

As this vapour ‘drive’ occurs and forces moisture toward the cold outer surfaces of the building structure, impermeable materials such as glass, steel, plastic and traditional aluminium sarking materials cannot allow it to escape. As a result, there is a risk that condensation can form on the inside of the building, just as mist or droplets of condensation form on the inside of a window on a cold night.

To minimise this risk, the Enviroseal membranes allow moisture to easily pass through the sarking with minimal resistance, allowing any condensation formation to occur on the outside of the building as shown in Figure 1.

Where condensation forms in your home

A highly vapour permeable, tough, light duty wall wrap for use as a sarking in timber and steel frame wall construction.
A range of wall wrap products provide a secondary protective skin to your home which can reduce draughts and help make your home more comfortable.
A high tensile roof underlay designed to reduce the risk of condensation damage and weather related water entry in the roof.
Multi-layered non-permeable membrane specially made for residential roofs to help insulation work more efficiently and protect the things you value from storm driven rain and dust, condensation and bush fire ember attack.
Designed specifically for metal roofs, Bradford Anticon combines Bradford glasswool blanket with an impermeable foil facing, that protects your home from the condensation that can form under metal roofs.
Energy efficient, innovative home ventilation for comfortable living. Brought to you by CSR Edmonds.

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