Rain penetration through masonry (known as penetrating damp) is a common problem in buildings – particularly in the case of those of solid wall construction. The problem is also increasingly common in buildings of cavity wall construction where cavity wall insulation has been poorly installed or used in walls that are not suitable for cavity wall insulation. Other paths through which rain can cross through a cavity wall include incorrectly positioned wall ties and mortar obstructions in the cavity.
Older buildings, especially with solid walls, are more likely to suffer from penetrating damp. Be aware that the symptoms can often take weeks or months to appear. There are a number of symptoms to look out for when identifying penetrating damp
Penetrating damp is caused by water permeating through walls from the outside. It can occur at all levels of a building but is more prevalent higher up. It is possible for damp to move within walls but this horizontal movement differs from the vertical movement of rising damp.