Airbrick

An airbrick is a special type of brick that contains holes to allow ventilation of air. It enables the circulation of air beneath suspended floors and within cavity walls to prevent moisture building up as a result of cold or damp air ‘sitting’ in voids or empty spaces.

Airbricks were traditionally manufactured using clay and later from cast iron, whereas modern airbricks are made from plastic. Plastic airbricks are more durable and enable a greater rate of airflow. An alternative to airbricks is the use of cast iron grilles, known as air vents.

In addition to helping prevent damp and rot setting in to timber floorboards, the airflow provides ventilation for solid fuel fires, stoves, gas heaters, and so on.

Airbricks should be located and installed so as to maximise the cross ventilation in the underfloor voids, and should be kept clear of obstructions. A consideration when installing a conservatory is that airbricks on the wall of the house can be blocked by the concrete slab on which the conservatory is built, but more generally they can be blocked by vegetation, earth, and so on.

Airbricks can be positioned either above or below the damp proof course (DPC) level, and should ideally be incorporated on all sides of a building, typically at least 75 mm above the ground.

A disadvantage of using airbricks is that the small holes can allow pests such as mice, slugs, and wasps to enter a building. A possible solution is to fix wire mesh over the airbricks, or use specially-made airbrick covers, which can prevent entry of pests, although care should be taken to cover all airbricks.

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[edit] Related articles on Designing Buildings Wiki

• Brick.
• Cavity wall.
• Condensation.
• Damp.
• Natural ventilation.
• Thermal comfort.
• Types of floor.
• Underfloor air distribution.
• Ventilation.
• Weep hole.