Rain penetration through masonry (known as penetrating damp) is a common problem in buildings – particularly in the case of those of solid wall construction like many buildings constructed prior to 1930. 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.
Frost damage, moss growth, carbon deposits, spalling brick, internal damp and bossed render are all problems caused by penetrating water. The most common visual symptom of rain penetration is damp patches on the internal walls – often causing paint to flake or wallpaper to peel. However damp masonry caused by penetrating damp can also result in a wide range of other symptoms including:
• Reduced thermal resistance of damp masonry – causing heat loss and condensation - mould & fungicide
• Moss and mould growth
• Frost damage
• Rotting of embedded timbers
• Disfiguring carbonate deposits
• Bossed Render & Spalling brick