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Wet Rot FAQs

Rotten wooden timber roof structure

A Garratt’s Damp & Timber, we are experts in all aspects of damp proofing. This includes timber issues like wet rot. We are often called out to properties that are experiencing issues with wood rot, and more specifically, wet rot.

It’s a common issue that affects thousands of properties across the UK, but despite its prevalence, many people are not familiar with wet rot and, understandably, have questions about it. Whether you own your own home or rent, everyone can benefit from knowing the signs of wet rot. The quicker it’s identified, the faster it can be treated and the less damage there will be.

We’ve put together this handy FAQs guide on wet rot, detailing everything you need to know about the issue and how you can go about eradicating it.

What is wet rot?

Wet rot is the name given to a group of fungi that flourish in timber with more than 28% moisture. There are a number of types of fungi that fall under the wet rot umbrella, with brown and white rot being the 2 categories. Once the fungus has found its way into timber, it begins to eat away at it, causing it to rot and become structurally compromised. Depending on where the issue is located, this could be detrimental to the safety of your property.

What does wet rot look like?

There are a number of tell-tale signs associated with wet rot, making it relatively easy to spot. The first symptom is a mycelium growth. This commonly takes the appearance of a grey/white web (mine fungus) or black root like strands (Cellar Fungus). The fungus will extend across the timber to find a continuous food source. This is not to be confused with dry rot mycelium growths which can appear on both wood and masonry – wet rot cannot survive in less than 30% moisture, so the growth will be limited to the affected timber only.

Another sign of brown wet rot is visible cracks in the timber. They will typically take the shape of a cuboid. As a result of the structural issues within the wood caused by the cracks, you may find that the timber is extremely brittle and crumbles easily upon touch.

Furthermore, keep an eye on the colour of the wood. Wet rot only survives in damp environments which means the timber will look darker than its original colour (brown wet rots) due to the excess moisture making the wood wet. coupled with a musty smell or a springy, spongy feel (particularly on floorboards), there’s a good chance that your property is experiencing wet rot.

White wet rots tend to lighten the colour of timber and results in stringy, fibrous damage to the wood and not the cuboidal cracking associated with brown wet rots.

 Why does wet rot occur?

Wet rot is the result of excess moisture in timber. There are several reasons why wood in your property may have a high moisture level, with a burst pipe or plumbing leak being one of the most common. Another leading cause is a crack or hole in the roof. This can allow cold air and rainwater to get in, causing enough damp for wet rot to survive. Additionally, if you don’t have adequate ventilation in rooms like the kitchen or bathroom (areas with high humidity), this could contribute to the likelihood of your property developing wet rot.

Where does wet rot happen?

Wet rot can occur anywhere; however, it is most common in the kitchen, bathroom, sub-floor voids or loft. This is because the kitchen and bathroom have pipework that can leak or burst, and the very nature of them is humid, meaning they are more prone to damp issues. The loft is susceptible to roof or guttering issues, making this a hotspot for wet rot, too.

That being said, wet rot isn’t unique to these areas and can occur anywhere where the moisture content of the timber exceeds 28% including joists, floorboards and skirting boards.

Can wet rot cause health issues?

The presence of wet rot can cause mould spores, and if breathed in, these can affect your health. Those with asthma or eczema are most vulnerable to mould spores.

How quickly does wet rot spread?

Wet rot will thrive as long as there is moisture within the affected timber. It won’t spread through masonry, unlike dry rot, which means it is easier to contain. That being said, affected areas can deteriorate quickly and cause significant damage, so as soon as the issue is noted, you should work to fix it.

How is wet rot treated?

How to treat wet rot depends on the cause. For example, if the issue is caused by a leaking pipe, the main route of treatment is to fix the pipe. If the problem is caused by a loose or damaged roof tile, you will need to replace the tile. When you have successfully detected and halted the cause of the water ingress, the affected timber will need to be inspected. If the severity of the problem is minimal, you can likely get away with allowing the wood to dry out naturally.

Alternatively, if the damage is more severe or widespread, a chemical may need to be used to kill the fungus. If structural damage to the timber has been incurred, the timber may need to be replaced altogether. It is best to get a professional company in to determine the cause of the wet rot and the plan of action thereafter.

How much does wet rot treatment cost?

The cost of treating wet rot depends on the cause of the problem, the extent of it, and whether the timber needs to be replaced. We will conduct a site survey to assess your property and try and identify the cause of the problem, and we will then give you an no obligation quote based on our findings.

Can wet rot be prevented?

In short, yes, wet rot can be prevented. How to prevent wet rot largely comes down to basic property maintenance. This includes ensuring there is adequate ventilation in high humidity areas (extractor fans, clear vents, and open windows), checking that guttering is in good condition, making sure roof tiles are not broken or damaged, and keeping an eye on pipework to ensure any potential leaks are caught in good time.

Learn More About Wet Rot 

Hopefully these FAQs have answered some questions you may have had about wet rot. If you still have a query, or if you suspect you have wet rot and want to book a site survey, please contact us.

Call us at 0208 535 7536

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