Causes and solutions for exterior wall moisture and insulation

Moisture in exterior walls is a common issue caused by rising damp from foundations, poor insulation, or damaged joints and facade finishes. Rising damp occurs when groundwater is drawn upward through porous building materials like stone, concrete, and mortar via capillary action. While modern homes typically feature horizontal moisture barriers, older properties are more vulnerable due to the absence of these protections or structural weaknesses developed over time.

To combat moisture and improve energy efficiency, homeowners can utilize facade impregnation and insulation. Impregnation makes walls water-repellent without losing breathability, allowing moisture to escape from the inside while causing rain to bead off.

Insulation methods vary based on construction. Cavity wall insulation is often the most cost-effective option for suitable homes, as material is blown into the existing gap. For homes without a cavity, exterior or interior wall insulation are alternatives. While exterior insulation is more invasive and expensive, it can offer higher long-term returns for specific structures.