What is wet rot?

In this article we will be looking at wet rot treatment.

In simple terms, wet rot is when high moisture levels in a property cause timber to decay naturally. It’s a catch-all term that is used to categorise a wide range of fungal species that are responsible for the condition. The most common of these is Coniophora Puteana, or ‘Cellar Fungus’. Here is everything you need to know about not just what wet rot is, but also what its causes are, how wet rot can be identified and what solutions there are for wet rot treatment.

Wet rot should not be confused with dry rot. This is a good thing because although both are caused by high moisture levels and fungal growth, dry rot is far more serious. Despite its name, dry rot also needs moisture to grow. Such moisture can come from sources such as damaged guttering or a leaky pipe.

Dry rot differs from wet rot in that it often lies in areas of the home that are hidden from view, such as underneath floorboards. Dry rot is one of the most damaging conditions that can afflict a property. It spreads aggressively, so much so that it is sometimes referred to as ‘the cancer of buildings’. It is so destructive that it can seriously impact on the actual structural integrity of a property.

Wet rot, if left untreated, will weaken timber and can lead to structural damage, but it does not spread through masonry and its growth will be halted once the wet rot treatment has removed the moisture source.

The causes of wet rot

In virtually all cases, wet rot causes will be attributable to a structural defect in the property which is allowing water to gather on timber surfaces. This could be from rainwater, condensation, or from the plumbing in the property.

The cause of wet rot in a property usually occurs when the integrity of certain parts of a property have been compromised. This could be from the guttering and drainpipes or from the roof tiles. Cracks in the brickwork or cracked water pipes are a common cause, as well as overflowing water cisterns and tanks. Persistent condensation in a property and those that are poorly ventilated are further causes of wet rot.

Properties that have a damaged damp proof course (or no DPC at all) are also susceptible to wet rot problems.

How to identify wet rot

This is no exact science, but checking the integrity of the areas of the home where water could be being released from, such as pipes and gutters, is a good start.

There are a several tell-tale signs of wet rot to look out for. Look for flaky paint around the home. If paint is damaged, the risk of wet rot is increased. You can test the potentially affected area by inserting a sharp knife into the wood. If the blade goes into the timber easily, it’s a clear sign of wet rot underneath the paint.

Doors and window frames that look discoloured or bleached could be affected. They will look darker than they should and will feel soft to the touch. Any localised fungal growth on timber is another indicator of wet rot, and often there will be a musty, damp smell too.

Solutions and wet rot treatment

There are several solutions and wet rot treatments to solve the problem when diagnosed.

The first and by far the most important step in wet rot treatment is to identify the moisture source and address that issue. The areas affected by wet rot must then be allowed to dry out so that treatment can begin.

One option is to have a professional wet rot survey undertaken on the property. This will assess the extent of the damage and inform an appropriate course of action. In most cases the infected timber can simply be cut away. New timber, treated with fungicide, can then be put in its place. In more severe cases, timber might have lost so much of its strength that it needs to be entirely removed. A new pre-treated timber will then be installed.

The worst case scenario is if the structural timbers of a property, such as floor joists, are infected with wet rot. If this is the case, then expert advice should be sought, as the structural integrity of the building may have been affected.

However, in the vast majority of cases, if the wet rot has been identified soon enough, localised removal of timber is usually sufficient. Various DIY repair kits are available to use. Primers should be applied to replacement timbers and preservative tablets that can be inserted into the timber next to the repaired area can offer further protection.

Prevention is better than cure

Fortunately wet rot treatment is usually relatively straightforward once the problem has been identified and established. However, it’s sensible to take some basic preventative measures to limit the chances of wet rot occurring in the first place. Carry out regular checks on areas where it is possible for water to ingress. In older homes, wet rot is likely to be more of an ongoing issue. Other steps to take include clearing soil and debris away from any timber frames, and ensuring that all external timber frames are painted to protect them.