Wet Rot vs Woodworm: How to Tell the Difference
Wet rot and woodworm can both weaken timber, but they are different problems. Wet rot is fungal decay caused by persistent moisture. Woodworm is damage caused by the larvae of wood-boring insects. Correct identification matters because the repair and treatment should match the cause.
WET ROT AND WOODWORM ARE NOT THE SAME
Wet rot develops when timber remains damp enough for decay fungi to grow. Woodworm describes insect attack in timber. A piece of wood may show one problem, or both may be present where damp conditions have made the timber vulnerable.
SIGNS OF WET ROT
Affected timber may feel soft or spongy, split along the grain, change colour or crumble when pressed. Damage is usually concentrated around a moisture source such as a leak, penetrating damp, defective plumbing or poor sub-floor ventilation.
Once the moisture source is removed and the timber dries, wet rot normally becomes inactive. Timber that has lost strength may still need repair or replacement.
SIGNS OF WOODWORM
Typical signs include small round or oval flight holes, fine powder or gritty frass, damaged edges and weakened timber. Old holes alone do not prove that an infestation is active. A survey should consider fresh debris, the condition of the holes, the timber species, moisture levels and any live insects.
WHY MOISTURE STILL MATTERS
Some wood-boring insects favour damp timber. That means treating visible holes without investigating leaks, ventilation or damp masonry can miss an important part of the problem.
Wet rot also cannot be solved by applying a timber treatment alone. The building defect that keeps the wood damp must be corrected.
HOW A PROFESSIONAL INSPECTION HELPS
A useful inspection assesses the type and extent of damage, timber moisture, nearby building defects and whether structural strength has been affected. Concealed joists or floor voids may require further access before the full extent can be confirmed.
Treatment should be proportionate. Sound timber should not automatically be removed, and insecticide should not be applied merely because historic flight holes are present.
WHAT REPAIR MAY INVOLVE
The correct plan may include stopping water entry, improving ventilation, drying the structure, repairing or replacing weakened timber and applying an appropriate treatment where active insect attack is confirmed.
Where important structural members are affected, additional structural advice may be necessary.
WHEN TO ARRANGE A SURVEY
Arrange an inspection if floors feel springy, skirting crumbles, fresh frass appears, new flight holes are noticed or a musty smell persists. Renovani investigates damp-related timber problems and suspected woodworm across Sussex and Kent.
Timber service: https://lanternfish-begonia-586n.squarespace.com/timber-treatment
Book a Professional £50 Damp Survey: https://lanternfish-begonia-586n.squarespace.com/surveys-50
