Dry Rot, serpula lacrymans

Timber may be attacked by many species of wood-rotting fungi, the most widespread in Britain being the True Dry Rot Fungus, Serpula lacrymans. When spores from this fungi settle on damp wood they germinate and develop fine, thread-like filaments called hyphae. Each hypha releases enzymes, which break down wood cells, causing loss of timber strength. Fungi cannot attack wood at or below about 20% moisture content so decay does not occur unless dampness in buildings arises through poor design or building faults.

"Dry rot" is the term used for decay caused by Serpula lacrymans, the True Dry Rot Fungus. It is a brown rot that destroys the cellulose component of wood, eventually reducing timber to a dry and crumbly consistency - hence the name 'dry rot'
Dry rot is the most serious type of timber decay in buildings because it can cause rot at a lower moisture content than wet rot fungi and it has the ability to grow through damp masonry and brickwork, and behind plaster. It can therefore spread rapidly through a building, making treatment both complicated and expensive.

Dry rot has been a problem in wooden structures for centuries, with some of the earliest documented accounts coming from the Royal Navy of James I in the early seventeenth century. Since then it has moved on from ships to buildings and is now found throughout Britain. It is most prevalent in the north and west of the country and in buildings constructed before the Second World War.

Warning signs

• Rust/dark orange coloured spore dust around Sporophore
• Spore dust may also be evident at bleed areas such as gaps under skirting boards or in areas with no carpet such as understair cupboards
• Strong smell of mushrooms around the fungi
• White mycelium, can be similar to heavy spiders web or white pillows of cotton wool, depending on humidity
• Gray white coloured hyphae (may look like a vine with no leaves)
• Timber is scarred with deep cracks across the grain, becomes light in weight and crumbles easily between fingers.

If you are an accomplished DIYer or have a good local joiner you can call on, you could tackle most rot problems with the advice and resources in our guide Dealing with Wood rot

I would however recommend contacting a specialist company with a fully reliable guarantee to carry out any eradication work for Dry Rot. Dry Rot has a nasty habit of returning if even the slightest trace is left behind following treatment. Professionals can have problems with this fungi and I personally would not be happy trusting a smaller outfit to return time after time, free of charge if the problem persists. If you have, or suspect you have dry rot, click to request a Free Inspection

• rotting wood
• mold on wood
• growth on skirting
• fungus
• rentokil
• mushrooms
• dry rot
• rot
• rotten wood
• mould under floor