Mould above window

The presence of mould within the head of this window reveal is directly linked to issues stemming from the adjacent concrete slab porch roof, which has been in place for approximately 100 years. Over time, the concrete has significantly deteriorated, losing its structural integrity and becoming porous. As a result, the slab now absorbs and retains rainwater, making it a persistent source of dampness.

This retained moisture not only compromises the roof itself but also affects the adjoining interior spaces. The saturated concrete creates a thermal bridge, effectively acting as a cold spot within the building. When warm, moist air from the interior comes into contact with this colder surface, it cools down rapidly, leading to condensation. This accumulation of moisture on the cold surface provides an ideal environment for mould growth.

The mould is a clear indication of prolonged exposure to these unfavourable conditions and reflects a combination of both external water ingress and internal condensation issues. Addressing this problem will require a thorough assessment of the porch roof’s condition, possibly involving repairs or replacement to eliminate the root cause of the moisture ingress, and improving the insulation or ventilation around the affected area to prevent recurring condensation.

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This job was located in Rochester, Kent.