Last edited 12 Dec 2017

Barrier wall system

The term ‘barrier wall’ is used to refer to a system of external wall assembly that maintains weather-tightness by preventing the intrusion of air, water and vapour. Barrier walls rely on the integrity of the outermost surfaces and construction joints, and are considered a cost-effective alternative to cavity or solid wall assemblies.

The cladding material should be impervious to the elements. Common examples of barrier wall systems include:

The exterior cladding in a barrier wall system serves as the main drainage plane – the element exposed to the weather. This differs from a cavity wall system where the main drainage plane and defensive line against bulk rainwater penetration is inside the cavity.

Careful installation of a barrier wall is crucial as the joints between facing units must be well sealed. The gaskets and caulking must be installed so that no water and/or air vapour can leak inside the cavity and damage the building envelope. There are often complex interface details that require specialist installation by professionals.

Although barrier wall systems often have a lower initial cost, this should be considered alongside the fact that they require a relatively high level of routine maintenance to remain effective over time as continued exposure to wind and rain can degrade the seals and lead to failure. Typically, they tend to be installed makes them more accessible should inspection or repairs be required.

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