Soft brickwork and mortar, bubbling paint, and damp and mouldy internal walls are signs of rising damp.

A musty, dank odour may also be present.

CAUSE Rising damp occurs if there is a damaged or inadequate dampcourse. This is the impermeable layer of metal or plastic that is installed below the floor level of an external brick wall.

Renovated concrete patios are often built above the dampcourse line and can contribute to rising damp. It is quite difficult to fix andthe dampcourse will need replacing.

SOLUTION Use an anti-fungal spray on visible mould and increase ventilation to the affected rooms until the work’s done. Boost subfloor ventilation to reduce the chance of a recurrence.

If left unchecked, toxic black mould will bloom, and interior lime render can crumble and fall off.

In the long term, it may damage the wall’s structure. In concrete walls, steel reinforcing within may rust and expand, causing cracks.