Surveyor showing dry rot

Dry Rot

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How to Identify Dry Rot

Dry rot is a type of wood-decaying fungi that can cause severe structural damage to buildings by weakening and destroying the timber found in floorboards, skirting, joists and other wooden surfaces. Our guide has been designed to help you identify dry rot and how to spot the signs so that you can take action early and reduce the potential costs associated with repairing dry rot problems.

If your home or business is experiencing issues with suspected dry rot, we would recommend a professional timber survey to be conducted on your property. Get in touch with our team today on 0800 0121 437 or click the button below to book a thorough property survey with our rot specialists.

What Is Dry Rot

Dry rot means the presence of a wood-destroying fungus called Serpula Lacrymans. This fungi is a type of brown rot that feeds off the cellulose or lignin found in timber to leave it cracked, brittle and weak. Severe dry rot problems will eventually damage the structural integrity of the property and leave wooden timbers beams and joists structurally unsafe.

Dry rot differs from other types of wood rot because it will spread over and through other damp materials or masonry to the rest of the house far beyond the initial infestation site, whereas wet rot will remain localised to the source of moisture.

How to identify dry rot

Spotting Dry Rot Symptoms

Dry rot is one of the most serious property problems there is, so identifying the signs early is the best way to prevent further damage occurring.

The following signs and symptoms will help you to understand what the fungus looks like, so if you notice all or any of the symptoms we list below then it suggests you have a problem and should consider arranging for a survey from a qualified professional for advice and help on how to repair your home.

If you have read our guide, but are still unsure if there is a rot outbreak in your property, then contact our team to arrange a professional survey.

What are the Differences Between Dry Rot and Wet Rot?

Without industry training and experience, it can be difficult to differentiate between dry rot and wet rot due to the fact that both types of rot share a number of tell-tale signs.

Both these forms of rot cause timber to crack, leave affected areas soft and spongy and can lead to fungus-like growth on timber.

One of the main differences between dry rot and wet rot is that wet rot requires a higher moisture content of around 50% whilst dry rot will grow with a moisture content of around 20-30%. Because of this, wet rot will only be present near a prevalent moisture source and as such is often found in the vicinity leaking appliances, burst pipes or window sills. In contrast, dry rot can spread over relatively dry timber if the humidity is right.

Due to the difficulties in identifying the type of rot, we would recommend contacting a rot specialist who can examine any affected timber and establish if there is a rot outbreak

What Are The Signs Of Dry Rot

Damp Smell - The Dry rot smell is a distinct musty mushroom smell.

Spore Dust - Large concentrations of fine brown dust can indicate an outbreak of dry rot is present.

Hyphae - Fine strands of fungal growth dry rot spores produce when they come into contact with timber in damp and humid conditions. They grow by extracting the moisture from timber.

Mycelium - As the hyphae grow, the strands combine to form a white cotton wool-like fungus called Mycelium to spread to new timber surfaces.

Timber Decay  - As it develops, timber affected by the fungus will begin to discolour, darken and become brittle with cuboidal cracking.

Dry Rot Fungus - A mushroom-like orange fungus, the fruiting body of dry rot can be found in warm, damp, dark ventilated places to grow such as under floorboards, cavity walls or in the attic.

You may wish to take a look to see how these rot symptoms differ from other signs of damp on walls.

What Causes Dry Rot

Dry rot spores are always present in the atmosphere, however, they are harmless unless the right conditions are present. To develop into an infestation, a damp problem and a lack of ventilation are required in the property

Dry rot starts when these spores land on timber with moisture content over 20% they will then begin to germinate and produce hyphae (fine strands of fungal growth) that are greyish in colour. This will develop into mycelial growth which varies from grey to pure white in wet conditions. It is at this stage in the dry rot life cycle that Sporophores or fruiting bodies will begin shedding millions of spores in the form of red dust, so the process repeats itself and the infestation becomes more entrenched in the home.

Although individually these spores are almost invisible to the naked eye, In houses with dry rot problems you will often find that when they group together they appear as a tell-tale fine orange or brown dust.

How Does Dry Rot Spread

Once the hyphae strands are formed, they join together to create a mass called Mycelium which can vary in colour from grey to pure white, and these strands grow into and across damp wood and masonry. It can also grow over materials such as plaster, mortars, bricks etc as it searches for more cellulose-containing timber to feed on.

When the growth is advanced a fruiting body (Sporophore) may develop. This fruiting body takes the form of a “fleshy pancake”, the surface of which is orange/ochre-coloured.

How to Deal with Dry Rot

Despite the serious nature of wood rot, if dry rot is identified quickly, a less invasive and more cost-effective treatment will be required. During our dry rot treatment plan, our expert team of surveyors and technicians will assess the extent of your dry rot problem before carrying our remedial repair work to resolve your dry rot issue.

For any wood rot treatment, we aim to:

  • Remove the moisture source and promote rapid drying of timber with high moisture content
  • Application of fungicides and biocides repair damaged wood
  • Kill off the existing infestation
  • Replace any damaged timbers with pre-treated timber
  • Prevent further attack

You can read more about our process on our dedicated dry rot control page.

Will Dry Rot Come Back

Dry rot is notoriously difficult to fully eradicate and that is why you must ensure the specialists you instruct to solve the problem offer real and meaningful long term guarantees.

Our long and proud trading history alongside the strength and capabilities that come from our being an industry powerhouse like Rentokil Property Care ensures you know we will be there for you in the future should you see signs that dry rot is returning to your property.

Contact Our Dry Rot Specialists

Our damp proofing and dry rot experts are only one phone call away from resolving your Serpula Lacrymans problems. If you suspect or are unsure if your property could have dry rot, we are here to help.

Our team of locally-based specialists are experienced in identifying, removing and treating dry rot with approved fungicidal solutions. Click on the button below to complete our online form 0800 0121 437 to book a dry rot survey.

More Wood Rot Help & Advice

For more help and advice to identify and treat wood rot take a look at the links below.