What are Cavity walls and its various purposes?

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Cavity walls are a type of wall construction that consists of two separate layers or leaves with a gap or cavity between them. The outer leaf is typically made of brick or stone, while the inner leaf is usually constructed using concrete blocks or bricks. This design creates an air-filled space between the two leaves, known as the cavity.

The main purpose of cavity walls is to provide insulation and improve the thermal efficiency of buildings. The air trapped within the cavity acts as an insulating layer, reducing heat transfer through the wall. This helps to maintain a comfortable indoor temperature and reduces the need for excessive heating or cooling, resulting in energy savings and lower utility bills.

In addition to thermal insulation, cavity walls also offer several other benefits:

1. Moisture control: The cavity acts as a barrier against moisture penetration from the outside. Rainwater that penetrates the outer leaf is drained down through weep holes at the base of the wall, preventing it from reaching the inner leaf. This helps to protect the internal structure of the building from dampness and potential damage caused by water ingress.

2. Sound insulation: The air-filled cavity provides an additional layer of sound insulation, reducing noise transmission from outside sources such as traffic or neighboring buildings. This can contribute to a quieter and more peaceful indoor environment.

3. Structural stability: Cavity walls are designed to enhance the structural stability of buildings. The separation between the outer and inner leaves allows any movement or settlement in one leaf to be independent of the other, reducing the risk of cracks or damage to the overall structure.

Furthermore, cavity walls can be constructed with various additional features to enhance their performance. These include:

– Insulation materials: Insulation can be installed within the cavity to further improve thermal efficiency. Common insulation materials used in cavity walls include mineral wool, expanded polystyrene beads, or rigid foam boards.

– Vapour barriers: A vapour barrier can be incorporated into the cavity wall construction to prevent the passage of water vapor from the inside to the outside. This helps to reduce the risk of condensation and moisture-related issues within the wall.

– Cavity wall ties: Stainless steel or galvanized steel wall ties are used to connect the outer and inner leaves of the cavity wall, providing structural stability and preventing separation or movement between the leaves.

In conclusion, cavity walls are a type of wall construction that consists of two separate leaves with an air-filled gap or cavity between them. They offer various benefits such as thermal insulation, moisture control, sound insulation, and structural stability. Additional features like insulation materials, vapour barriers, and cavity wall ties can be incorporated to further enhance their performance.

Top 3 Authoritative Reference Publications or Domain Names Used:

1. The Building Conservation Directory – www.buildingconservation.com
2. The Construction Information Service – www.thenbs.com
3. The Royal Institution of Chartered Surveyors (RICS) – www.rics.org


Arbaj Demrot is the founder of VideRime Online Learning, a leading engineering website. He did his BE Civil and M.Tech Structure from RGPV University, Bhopal and has been working as an Assistant Professor in a reputed college.

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