Dry Rot

Decay of timber can take place in three forms; wet rot, dry rot and woodworm.

Dry Rot

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Dry Rot is a fungus called Serpula Lacrymans, a type of wood rot.  It is less common than wet rot but it is more devastating and can spread to and infect parts of the structure that are relatively dry, attacking timbers several metres from its source, travelling along masonry and other non-timber objects.  Under ideal conditions it can spread very quickly. Therefore it is imperative that it is identified correctly and speedily before it causes too much severe structural damage.    

Identifying Dry Rot

To diagnose dry rot, an inspection by a competent surveyor must be carried out when wood rot is suspected. Our expert surveyors will carry out a full building survey; a comprehensive and systematic inspection is essential to ensure that there is no rot concealed.

002 dry rot wet rot timber splice repair damp timber truss wood belfast dublin northern ireland NIUsually the first and best signs of dry rot are;

  • Red/brown timbers which are crumbly, dry and brittle.
  • Rusty red dust; frequently seen around fruiting bodies.
  • Growths on the timber which are grey or white strands up to 8mm thick.
  • Silky white cushions of fungus in dark damp areas.   
  • Thick silvery grey sheets of fungus in less damp conditions. Patches of yellow and lilac occur if exposed to light.001 dry rot fruiting body wet rot timber damp dampness dampproofing dpc boron belfast dublin northern ireland NIdry rot, fruiting body, decay, wet rot, timbe splice repair, damp timber, truss, wood, belfast, dublin, northern ireland, ni

Causes Of Dry Rot

Dry rot fungal spores will easily spread in timbers in the 'right' conditions.  That is, timbers subjected to damp conditions with no ventilation.  Dry rot is therefore always caused by moisture penetrating the building fabric (which can be as a result of rising damp or penetrating damp).  It is important that the damp problem is eliminated; otherwise the problem is likely to re-occur.

Dry rot, as well as being unsightly and creating an odour, causes the timbers to lose its strength, with the possibility of structural failure of the timbers in extreme cases.  

Dry Rot Treatment

When treating dry rot, the initial priority is to eliminate the source of damp and promote rapid drying of the structure. To achieve proper drying can be difficult. Any damp may be the catalyst for a future outbreak.  All affected timbers need to be removed and replaced. Dry rot mycelium growth on timber stud - NI - N Ireland - Northern Ireland - England - Scotland - wales - Dry Rot

In addition, in order to provide real protection against fungal decay the timbers should be protected with preservatives, and the masonry sterilised using products, including:

  • Fungicidal masonry treatment
  • Deep penetrating timber preservatives: boron preservative
  • Anti-fungicide plasters
  • Physical barriers and damp proof materials

Dry Rot Sensors

Where the timbers are large or in hard to reach places, a dry rot sensor may be used to prevent unnecessary opening up, especially where decorative elements are in potential dry rot areas.  A sensor is placed in predrilled 7mm holes, at specific locations, and left for 14 days.  The sensor is checked; a change in colour signifies that dry rot is present. If there is no change, then the sensors may be left in place for further monitoring. 

Wet Rot002 dry rot wet rot donegal timber damp dampness damp proofing splice repair belfast dublin northern ireland NI

Wet rot is a wood rot, found mainly at the bearings of timber joists in external walls, for example at the sole or head plates rather than in the studs. Wet rot decay of timber can take place only where the wood is maintained in persistently damp conditions.  Wet rot, though problematic, and could potentially lead to serious issues, is generally not as severe as dry rot, mainly because it does not spread like dry rot ie wet rot cannot spread across non-timber surfaces.

Identifying Wet Rot

Wet rot is found in timbers that have been exposed to dampness for a period of time. Generally, wet rot can be identified by:

  • The timbers feeling damp to the touch
  • The timbers looking discoloured (usually darkened), may be cracking, and feel softer, which may lead to the timber losing its strength
  • There may be some fungal growth
  • Damp, musty smell

Causes of Wet Rot

Wet rot is caused by the timbers being exposed to a regular source of moisture; leaking pipe, rising damp or penetrating damp, etc, over a prolonged period of time.  Wet rot, as well as being unsightly and creating an odour, can cause the timbers to lose its strength, with the possibility of structural failure of the timbers in extreme cases. 

Wet Rot Treatment

Initially it is imperative that the source of the damp is stopped.  This requires a full building survey by our experienced surveyors, as it can often be difficult to find.  Once the source of damp has been treated, then the wet and decaying timbers in the area must be removed and replaced.  Fortunately, unlike dry rot, wet rot does not spread through masonry, therefore once the affected timbers are removed, then so too is the wet rot.

Where the timbers are large or in hard to reach places, we specialise in removing the affected rotted timber, and replacing only the affected areas, using a technique called Timber-Resin Splice. Occassionally, the wood rot has caused the timber, often trusses, to slip and move out of position. Conventionally, the trusses would be lifted off by crane and repaired on the ground or in a workshop. Stronghold Preservation have experience in repairing the trusses insitu, and propping, lifting and jacking the trusses back into alignment (truss repair & realignment).

Where there has been evidence of damp in a building, and timber ends are bearing onto the masonry, we often prefer to treat these 'at risk' timbers with a water soluble boron preservative, to prolong the life of the timbers.

Our knowledgeable and experienced surveyors can carry out a survey to identify the type of wood rot, and the cause of the damp, and provide a comprehensive written report, detailing any remedial action required.  We will also provide a full quotation, where necessary.  Stronghold Preservation offer an insurance backed guarantee scheme for all remedial timber work.