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Dry rot

Dry rot can affect buildings of all ages and if decay is discovered it should be identified and remedial action taken without delay. 

Whether a modest basement flat or an important listed country house, dry rot can rapidly destroy timbers and building fabrics, leaving owners with extensive repairs that result in significant disturbance. Where it occurs, consequences can be serious if not tackled properly.  It can spread rapidly and will destroy timbers to sustain itself and regenerate by producing large numbers of spores.

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Timber Preservation

The root cause of dry rot affecting your property

Dry rot can only grow and survive because the wood that sustains it is wet. Humid still conditions are preferred so it is often found below wooden floors, growing behind wall linings or spreading behind window or door linings.

What sort of potential damage can dry rot do?

If left untreated and the conditions remain favourable, dry rot can cause extensive damage causing the disintegration of large structural timbers as well as skirting boards and window linings.

Dry rot can lead to the total collapse of building structures.

1. How it Occurs - The beginning

Microscopic spores are by dispersed by air currents. If they fall on damp wood and the right conditions persist they can germinate.


Dry rot early signs - spore dust - PCA

2. How it Occurs - When dry rot growth starts

Mycelium develops inside the timber and breaks down the wood for food.

The timber may darken in colour and shrink developing square cracks.


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3. How it Occurs - How it feeds

Dry rot will grow through certain structural types such as masonry. It will grow away from the timber it is feeding from and will move through even very small cracks in search of new timber to colonise and feed upon. 


Dryrot  - Homeowner Help & Information - PCA

4. How it Occurs - It can grow extensively

Dry rot can grow extensively on the surface of infected timber and in still, humid conditions, produces a mass of cotton wool-like growth. Water droplets are often produced on the surface of the mycelium.


Dryrot  - Homeowner Help & Information - PCA

5. How it Occurs - The fruiting body

After a period of growth, feeding and if in the right condition; fruiting bodies will eventually appear. Mature fruiting bodies will produce millions of additional spores that will eventually be released into the air that will begin the dry rot life cycle again. 


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A dry rot survey

In any situation where dry rot is suspected, the property should be the subject of a detailed survey by a specialist. The cause of the water ingress that allowed the dry rot fungi to become established as well as the full extent and damage caused must be fully established. 

Opening up and destructive investigations are often required to establish the extent of the dry rot. It is crucial that the surveyor identifies any timbers that have been damaged or structurally weakened by the fungi. 

To find a registered PCA specialist near you, simply use the search tool below. 

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