WEt rot

wet Rot

Wet Rot: Identification, Causes, and Effective Treatment

Wet rot is a common form of timber decay in UK properties, typically caused by prolonged exposure to moisture. Although less aggressive than dry rot, wet rot can still result in significant structural damage if left untreated. Recognising the early signs and understanding how to deal with wet rot is essential to protect your home or commercial property.

What Is Wet Rot?

Wet rot refers to a group of fungal species that attack damp timber, breaking down its structure over time. It thrives in consistently moist conditions, usually where timber has a moisture content above 20%. Wet rot commonly affects timber in contact with damp masonry, leaking plumbing, or areas with poor ventilation.

Unlike dry rot, wet rot does not spread through masonry or affect dry timber, but it can cause serious localised damage. It is most often found in basements, cellars, bathrooms, roofs, or under poorly ventilated floorboards.

Causes of Wet Rot

The primary cause of wet rot is excess moisture, which may result from:

• Leaking pipes or plumbing faults
• Defective gutters or downpipes
• Poor ventilation in subfloor or roof spaces
• Penetrating damp from damaged external walls
• Rising damp in ground floor timbers

Timber that remains damp over time becomes the ideal environment for fungal growth. If not addressed promptly, the affected wood loses its strength, becoming soft, spongy, and structurally unsound.

Signs of Wet Rot

Detecting wet rot early can prevent major repair work and costly damage. Here are some common signs to look out for:

• Timber that feels soft, spongy, or crumbly when touched
• Discoloured or darkened wood, often with a damp or musty smell
• Cracking, warping, or shrinking timber
• Fungal growth or a black/brown rotting appearance on the surface of the wood
• Peeling paint or bubbling wallpaper in damp areas

It’s important to differentiate wet rot from dry rot. While both thrive in damp conditions, wet rot is usually confined to the area where the timber is wet, whereas dry rot can spread more extensively.

Treating Wet Rot

Wet rot treatment involves eliminating the source of moisture, repairing or replacing damaged timber, and applying protective treatments to prevent future issues. The standard treatment process includes:

• Identify and fix the moisture problem – This might involve repairing leaks, replacing damaged guttering, or improving ventilation.
• Remove or repair affected timber – Severely decayed wood should be replaced with pre-treated timber. Minor damage may be repaired using timber preservative or specialist wood hardeners.
• Apply a fungicidal treatment – All nearby timber should be treated with a suitable wood preservative to kill any remaining spores and prevent recurrence.
• Improve airflow and moisture control – Ensure the area is properly ventilated to avoid damp conditions returning.

Preventing Wet Rot

Regular maintenance is key to preventing wet rot in your property:

• Check for signs of damp and fix leaks promptly
• Ensure good ventilation in roof spaces, bathrooms, and underfloor voids
• Keep external brickwork, render, and pointing in good condition
• Clear gutters and downpipes to prevent water overflow

Wet rot is a serious but manageable issue that affects many properties across the UK. With proper inspection, early intervention, and preventative maintenance, you can protect your home from the damaging effects of moisture and timber decay. If you suspect wet rot, it’s wise to contact a damp and timber treatment specialist for a professional assessment and solution.