Our client asked us to carry out a damp and timber survey due to damp walls. The victorian brick built semi-detached residential dwelling in Sheffield contained dry rot. The clients had lived in the property for almost 30 years. Within that time they had repair work externally to the roof and replaced the windows etc. They had never had a survey for damp. Like most properties of that period they had large cellars which they had not been down into for many years. The owner contacted us after seeing brown/red dust on skirting boards to the lounge. They also noticed damp walls that had caused the wallpaper to peel back. This is a common occurance for us to get a call regarding dry rot in Sheffield.
Our surveyor Jason arrived and after initial meeting the client carried out his survey, starting outside. Looking externally we survey guttering, ground levels, boundary walls as well as condition of pointing etc. to see if any of these items could cause any issues that could lead to damp walls. There was no real issues to the external elevations, just some minor pointing repairs. Internally we carried out our inspection of the ground floor, initially drawing a sketch of the property.
Jason then proceeds to use a Protimeter moisture meter to profile moisture readings on the various damp walls. Our team notice red dust on the skirting boards and window cill in the front lounge. Upon closer inspection the timber skirting boards were showing the tell tale signs of rot infestation. The boards were also shrinking which caused horizontal lines to run along the length of the board.
After recording high moisture readings on the damp wall our surveyor finally went into the cellar. We have seen many dry rot attacks in the course of our surveys though this one has to be one of the best in recent years. Fruiting bodies were found in numerous locations with extensive mycelium (roots of the fungus), was found running along walls and the timber. The fungus had been left unnoticed to cause serious problems to the timber floor and surrounding area. The rot thrived on the cellar not being ventilated and travelled throughout the cellar to look for new timber to attack. The Dry rot usually only affects timber that has a moisture content over 20 percent.
We explained to the client the serious issues relating to the dry rot which was the original cause of the decay. 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 should form the core of any dry rot eradication strategy. In this particular property with dry rot in Sheffield the initial dampness was that the property did not have a functioning damp proof course.
However, it is not always possible or practical to be sure that the timbers will remain dry in the long term. That is why it is so important to take secondary measures to defend against re-infection. Any affected timbers are removed and replaced with pre-treated timber. Any remaining timbers at risk of the dry rot are treated by an effective fungicide. Where the dry rot passes through the masonry, it will be isolated using physical containment and/or masonry sterilisation. Therefore, any dry rot prevention program needs to include strategies such as ventilation and waterproofing in order to ensure that timber cannot become damp enough to sustain the fungus.
If you would like information on how Cannon Contractors can help with dry rot in Sheffield, or any other damp problems in any town or city, then don’t hesitate to get in touch and our friendly staff will be happy to help.
Fungal outbreak and decay occurs when timber becomes wet for a sustained period of time. Depending on the type of dampness, this will determine the type of fungus that will develop. Wet rot and dry rot are types of wood destroying fungi. They cause significant issues to the fabric of a building and affect all buildings of any age. This is why it is crucial to identify the type of fungus.
Wet Rot: Will stay within the source of moisture and the timber will be wet in appearance.
Dry Rot: Will grow far from the source of the original moisture issue.
The most serious form of rot attack is dry rot – Serpula lacrymans – the true dry rot fungus. This fungus can spread to attack timbers that are away from the original source of dampness.
Whilst the name dry rot suggests that there is no moisture, this is not true. Dry rot actually requires moisture content of around 20% to form. A major difference between wet rot and dry rot is that dry rot will often occur in areas of the property that cannot be seen. This will cause significant damage when the problem is not dealt with.
Outbreaks of wet rot and dry rot develop in similar ways. Millions of microscopic spores disperse fruiting bodies of the wood-destroying fungi on air currents. They are not an issue generally though If they fall on untreated damp wood they will start to germinate. Mycelium (root system of the fungi) develops within the wood that start to use the wood for food. As the decay progresses the appearance of the timber darken and show a characteristic cracked appearance. Some wet rots may bleaching the wood, these are more common in doors and window frames. in time as the attack continues it weakens the timber so that it cannot carry out the role that it was intended, therefore causing serious structural issues.
Serpula lacrymans develops extensively on the surface of infected timber and in still, humid conditions produces a mass of cotton wool-like growth. The surface of the mycelium often produces water droplets.
Mycelium spreads over the timber surface by the continued growth and branching of the delicate hyphal threads growing with time. Specialised strands develop within the mycelium and these supply water and nutrients to the growing fruiting bodies. The strands assume their real significance when the fungus spreads from infected timber onto the surface of adjacent stone or brick walls. The tiny hyphal threads penetrate the mortar joints and plaster layers and large areas of damp wall can then become infected.
Typical indications of dry rot include:
This type of rot is caused principally by Coniophora puteana. Poria vaillantii is another important wet rot fungus and a number of less common fungi also occur. While each fungus has its own unique features, the general appearance of wet rot is similar – as is the treatment. Wet rot is typically confines itself to the area of dampness because the mycelium does not spread into walls.
It is important that the type and cause of the fungus are correctly identified before any corrective action. A survey of the timber with the fungi should be carried out by a competent specialist. This specialist will be able to tell if wet rot and dry rot are present. Once the survey has been carried out then a report containing the type of fungi and the treatment required. The key to the treatment is being able to identify the cause of the moisture that started the rot to take hold in the first place. Poor drainage, leaking radiators and a defective damp proof course are a few areas that often lead to damp timbers.
With wet rot there are no chemical treatments required, though replacement timber should be pre-treated from a timber merchant and the new timber should be protected by physical membranes to help protect the new timber.
For dry rot, chemical treatments are necessary and there are a different variety of application methods depending on the severity of the attack. Even plaster may need to be removed and the mortar joints could require raking out – as to the seriousness of the decay.
If you would like information on how Cannon Contractors can help with wet rot and dry rot, or any other damp problems, then don’t hesitate to get in touch and our friendly staff will be happy to help.