Cavity Walls Explained

Cavity walls are a popular feature of modern construction. They offer several advantages compared to walls of solid masonry, but they do need some care and attention. This article explains the purpose of cavity walls, their benefits, and the nitty-gritty of their construction.

The space between the two parts of a cavity wall is filled with air, which acts as an effective insulator. This reduces heat transmission into a building from the outside, and also helps prevent dampness. They are also cheaper to build than walls of solid masonry, and they provide protection against efflorescence, which is a build up of white marks on brickwork caused by water leaking through the external brickwork.

A cavity wall requires a gutter at its base to collect leakage water, drains to direct it away, and ties to anchor the two parts of the wall together. The ties must be corrosion resistant and adequately strong. They must also be free of any material that might form a bridge across the gap.

Today, there are a number of materials that can be used to insulate your cavity walls. The most common is expanded polystyrene beads (EPS). These are manufactured from a carbon polymer and subjected to steaming before they achieve the familiar shape you’re likely to see in most homes. Other popular materials include cellulose insulation, rock wool, and foam glass. The type of exterior and interior building materials will influence which one is best suited to your needs.