Diagnosing damp problems – what signs to look for

Signs of rising damp

Rising damp is caused by a non-existent or faulty damp proof course and describes the action of groundwater moving up through a wall through capillary action. Due to the nature of rising damp, only your ground floor will be affected by this type of damp. Signs of rising damp include:

• A noticeable tidemark on an interior wall up to 1.5m
• Peeling or flaking skirting boards
• Blistering plaster or paint
• White powder on walls (salts)

Signs of penetrating damp

Penetrating damp, otherwise referred to as water ingress, means that water is making its way into your home from the outside. This can occur in a number of ways, either via a burst pipe, leaky roof, or damaged masonry. Common signs of penetrating damp include:

• Localised damp patches on walls or ceiling
• Damp that becomes more visible when it rains
• Moss or algae growth on external wall
• Damaged brickwork
• Damaged guttering

Signs of condensation

Condensation is caused by poor ventilation and is the most common type of damp to affect UK homes. The root cause of condensation within a property is almost always poor ventilation. Condensation mostly occurring during the winter when the difference between external and internal temperatures is most dramatic. Signs of condensation problem include:

• Fogging on windows
• Black mould growth on windowsills, walls or even furniture
• Smell of mildew
• Blistering paint
• Peeling wallpaper

Signs of timber rot

It is important to catch timber rot before it has time to develop. Dry rot in particular spreads very easily throughout a property and weakens rafters and floorboards over time, to the point that they will eventually become unsafe. Dry rot and wet rot affect your timbers in different ways:

Signs of dry rot

• Damp, fungal smell
• Affected timber feels brittle and warped
• Deep cracks in the wood – often in a ‘cube’ formation
• Evidence of mycelium growth on timbers (white fluffy coating)
• Large fruiting bodies

Signs of wet rot

• Affected timber feels wet and spongy
• Affecter timber will appear darker
• Easy to crumble
• Damp, musty odour
• Look out for black fungus growth