Damp and Timber Specialists for 50 years

What is Dry Rot?

Dry rot is a specific type of rot known formally as Serpula Lacyrmans. Perhaps most well known due to its vastly destructive nature, the speed in which it can spread and the fact that it can grow over dry materials.

Dry rot can affect all forms of timbers including those which are pre-treated and can grow up masonry walls, often behind plasterwork or between cavities.

Due to the importance of correctly identifying and rapidly treating dry rot, Prokil have a dedicated team of expert surveyors available. They will be able to assist in identifying why the dry rot fungus has formed, what level of remedial work is required and ultimately how to best prevent its return.

What causes dry rot?

Dry rot in timber occurs when airborne dry rot spores come into contact with wet timbers. The spores germinate on those timbers which have a moisture content in excess of 28%, but best thrive when with levels are between 35 – 45%. The most common cause of dry rot in timber is blocked sub floor vents, timbers being in contact with damp masonry and from leaking pipe work. This prevents moisture under the property being ventilated. Although timbers which are treated with preservatives are at lower risk of fungal decay, dry rot has been known to attack and grow over these.

As dry rot in walls and under floorboards grows, it develops fruiting bodies. These are easily identifiable due to their rusty orange coloured fleshy structure and paler margins. Once matured, the fruiting bodies produce more rot spores which can spread over vast distances as they travel through the air.

Why is dry rot a problem?

Dry rot is by far the most destructive and fast spreading of rots. Under the right conditions, dry rot can spread from room to room within a short length of time. If left untreated, timber will continue to decay until they become structurally unsound. In worse case scenarios dry rot has been known to cause entire sections of floor to collapse. The presence of dry rot can also affect the value of your property. In this case, the longer it is left untreated, the lower the value of your property.

What does dry rot look like?

Dry rot is fortunately fairly easy to identify but can commonly be misdiagnosed as other types of rot. If you have any of the following symptoms present, we recommend you contact Prokil so that one of our experts can attend to carry out a survey to determine the type of treatment you require for dry rot.

  • Sheet like growth of mycelium, strands or fruiting bodies.
  • Large cuboid cracking of timbers
  • Musty odour; mushroom/ mouldy smell
  • The appearance of shrinking sections of skirting boards
  • Springy sections of floors
  • Timbers which easily break or crumble

Book a survey today

  • This field is for validation purposes and should be left unchanged.

What to expect from your survey


Book a survey

Book a survey from any of our locations, at a time that suits you.


Our experts give a quote

One of our damp & timber experts will arrive to survey the work.


We complete the work

Based on a quote, we carry out the work guaranteed for 20 years.