Wet rot under floor boards

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How to identify Wet Rot

Wet rot is a fairly common form of timber decay where fungal growth begins to spread on wooden surfaces with high moisture content or in damp conditions. Our guide will show you how to identify wet rot and spot the signs early to avoid serious damage to your structural timbers.

If you are worried about a potential wet or dry rot problem in your home then our specialists are the market leaders in identifying and treating all forms of wood rot. If you are concerned that you might have identified signs of rot in your home then read on for more information or book a wet rot survey today using the button below.

How to identify wet rot

What is wet rot

Wet rot describes a group of wood-destroying fungi (Basidiomycetes) that attack the cellulose or lignin in timber to leave it brittle and weak. Both brown rot and white rot are types of wet rot with the exception of Serpula Lacrymans - also known as dry rot.

Wet rots generally thrive on a higher timber moisture content than dry rot, but do not spread through masonry, and fungus growth stops when the moisture is removed.

The most common type of wet rot is Coniophora puteana (cellar fungus). Other species include Fibroporia vaillantii (mine fungus) and Phellinus spp.

What are the signs of wet rot?

To help you identify whether or not you have a wet rot problem we will break down the various signs that let you know what wet rot looks like

If you spot any of the following in your property then you will want to consider contacting a specialist damp and rot treatment team.

wet rot fungus under floorboard

Wet rot fungus

Wet rot fungus grows in stages. Early in its life cycle it will develop in strands called hypha that look a bit like spider silk forming into fern-shaped patterns. Depending on the specific genus of wet rot growing the colour will vary from brown rot to white rot.

These strands will later develop a white skin or coating and eventually a series of small fruiting bodies that look like tiny “off-white” mushrooms. This is known as Mycelium and is often accompanied by a musty smell.

This rot fungus cannot spread across other surfaces, but it can continue to grow and emit spores into the atmosphere.

Localised timber decay

Alongside potential structural damage, timber features such as skirting boards, window sills and floorboards often show physical signs of decay caused by wet rot such as paintwork on timber becoming damaged or showing signs of fungus appearing.

To assess if wet rot has affected the timber, take a flat-edged knife and insert it into the affected timber. If it easily penetrates then there is likely an issue with rot in the timber.

Damp smell associated with wet rot

Wet rot itself does not have a distinctive smell, however, the damp conditions that lead to fungus outbreaks often create damp and musty smells that should alert you that something could be wrong in the property.

If you can smell damp in your home and are unable to identify where it is coming from then we would always recommend that you seek the services of a qualified damp surveyor to diagnose the problem.

Timber lightens or darkens in colour

Wet rot can cause timber to change colour, darker or lighter depending on environmental factors, and this will coincide with a breaking down of the timber which makes it soft and spongy to touch.

Cuboidal cracking

Due to the high level of moisture, timber can begin to break down and cause a weakening of structural integrity of floorboards, wooden beams or whatever timber surface has been damaged by the fungus. In most difficult cases, the result of wet rot can create cracks in the timber resulting in a cuboidal pattern.

Where does wet rot grow?

Wet rot will grow on wood with a moisture content of between 30-60% This is usually caused by defects in plumbing, external guttering or pipework that create leaks. Wet rot thrives when these damp conditions combine with a lack of adequate ventilation.

A challenge associated with identifying wet rot is that it often develops in hard-to-spot areas of a property due to unseen water ingress. As a result, wet rot can be commonly found in damp basements, under floorboards, behind skirting boards and underneath leaking fixtures and fittings such as baths, toilets and washing machines.

What are the differences between wet rot and dry rot?

The most important difference between the two types of wood rot is that dry rot is far more aggressive and a much greater threat to your property than wet rot.

Unlike all species of wet rot which will remain localised to the source of moisture that allowed to grow in the first place, dry rot is only caused by the Serpula Lacrymans fungus which can spread far beyond the initial source and will actually spread across masonry and brick surfaces to attack fresh sources of timber. This means that wet rot does not cause dry rot and wet rot spores do not turn into dry rot fungus.

Other differences are that wet rot requires a high level of moisture content to begin to sprout, while dry rot spores will begin germinating at just 20 to 30% water saturation.

It is important to know that both types of wood rot share many similarities, and both require a damp environment to form. Identifying and diagnosing the type of rot present in your home can require the expertise of a qualified wood rot surveyor given that many of the signs and symptoms can also look similar to the untrained eye.

Is wet rot dangerous

The presence of wet rot is suggestive that there is a damp problem in at least a part of your property, however, the fungus itself is not dangerous to your health.

The danger from wet rot occurs to your property rather than your body. Due to the likelihood that the rot is likely to grow in hard to see places, it can go unnoticed for a long time. This puts affected wood, floors or even structural timbers at risk of becoming weak, brittle, and eventually unstable.

How wet rot occurs

One of the best ways to prevent rotten wood and fungal decay in your property is to make sure that condensation and other causes of wet and damp environments are negated by ensuring you have adequate ventilation in the home.

Another great way to prevent wet rot is by conducting routine checks of your property’s water management systems and pipes. This property maintenance will help to make sure wet rot doesn’t have the opportunity to germinate and grow undiscovered for any length of time.

How to fix wet rot

Once the source of water ingress and moisture has been identified and fixed appropriately, treatment can begin to repair the damaged timber. Wet rot treatment will vary depending on the extent of the timber damage and may require replacing any defective timber. Our timber repair specialists will try to retain healthy structural and decorative timber whenever possible. Any timber retained will be treated with fungicidal treatment to prevent further infections.

Also, for complete peace of mind for our customers, Peter Cox provide a 20-year guarantee on all of our wet rot treatments meaning that you can rest assured that your home will remain free from wet rot.

Your local wet rot specialists

If you suspect you have an issue with rot in your property, then do not hesitate to contact us. For expert advice or to arrange a professional survey with one of our surveyors, contact your local Peter Cox branch or book a survey online to speak to one of our experts.

Alternatively, the button below will take you to our online booking form.

Author: Steve Jameson CSRT CSSW

Steve is our National Operations Manager and there are few people in the industry with more experience treating wet rot. During his 30 years in the business, Steve has built a reputation as one of the nation's most experienced professionals in the field of rot and timber decay.

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