Dry Rot

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Dry rot (Serpula lacrymans) is a wood-destroying fungus. In the UK, it is best known for its ability to destroy timbers in buildings.

Typical indications of dry rot include:

If strands are touched a distinct mushroom smell is emitted.

Affected wood shrinks, darkens and has cuboidal cracks .

Cottonwool – mycelium develops under humid conditions.

Moisture – Teardrops can sometimes be seen on the fungus.

Fruiting bodies- a fleshy pancake or bracket with an orange-ochre surface forms.

Spores – Rust red coloured spore dust is seen .

Musty odour – Can be smelt when active.

Control and Treatment

Dry rot will only affect timber that is damp, typically affecting timber with a moisture content in excess of 20%. For this reason, removing the source of moisture ingress is vital.

Timber can become damp for a number of reasons. (e.g.) leaking roofs, rising dampness, or dampness penetrating through walls.

Any affected timbers should be removed and replaced with pre-treated timber. Any remaining timbers at risk of being affected by the dry rot should be treated with an effective fungicide. As dry rot strands can pass through brickwork and behind plaster it is essential that the true extent of the attack is discovered by removing plaster as necessary and irrigating brickwork to prevent the fungus becoming active again.

Advice and help

For more advise and help, contact

Andrew R Williams & Associates Ltd


0151 426 9660

01925 670 447

01744 644 042

0161 956 2358

Chartered Institute of Building, National Energy Services, Quantity Surveyors International, RICs and FPWS

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