Dry Rot / Wet Rot

Dry rot differs significantly from wet rot in that it is not necessarily confined to the area where the initial moisture problem has occurred and, under suitable conditions, can spread throughout a building. As a result, treatment typically involves a combination of measures, including the removal and replacement of timber that has become damaged or structurally weakened.

Treatment should also include the thorough cleaning of affected masonry using an appropriate masonry biocide. This is intended to eradicate fungal growth and help prevent the spread of dry rot through masonry and cementitious materials. Where timber is retained, an appropriate fungicidal timber treatment can be applied to eradicate fungal activity and provide ongoing protection against further attack.

Wet rot, by comparison, is generally much more localised. It requires elevated moisture levels, typically above approximately 28% and, depending on the species of fungus, potentially considerably higher, for fungal growth to become established.

Unlike dry rot, wet rot does not generally spread extensively through a building and is usually less destructive to timber. In most cases, fungal activity will cease once the underlying source of moisture has been identified and effectively controlled, such as by repairing a persistent leak or addressing another source of dampness.

Where timber has been significantly affected, removal and replacement may be necessary. Providing the underlying moisture problem is properly resolved and replacement timber is appropriately treated and installed, this will address the wet rot problem and the risk of recurrence.