What are cavity walls and how do I know if my home has them?
Cavity walls consist of two 'skins' separated by a hollow space (cavity). The skins are commonly masonry such as brick or concrete block. The concept of the cavity was originally introduced in the early 20th century to protect against water ingress to the inner walls of the property.
There are three simple checks you can undertake to assess the likelihood of your property having cavity walls. These are age of property, brick pattern and wall thickness.