Client: Domestic
Timberwise was given instructions to survey this property, with a specific request to determine the presence and extent of problems associated with wood rotting fungi. This semi-detached, stone constructed domestic property was occupied and fully furnished at the time of the survey. The weather conditions were sunny and dry.
The survey was restricted by:
- Fitted units
- Tiled walls
- Furniture
- Stored items
- Fitted floor coverings
External Observations
External defects in a property can lead to penetrating damp and subsequent internal dampness or cold bridging, leaving internal areas colder than other wall surfaces and prone to condensation.
There was no existing damp-proof course at the time of the survey. Ground levels to the left and right of the property were high in relation to the internal floors. This would likely lead to the lateral penetration of ground moisture. The front path structure abutting the front elevation is resulting in lateral penetration.
Dry Rot Observations
During our inspection, fungal decay was noted in the basement kitchen, ground floor hallway, front two rooms and first floor bathroom. This outbreak was identified as dry rot fungus (Serpula lacrymans). Our technicians could not carry out a full inspection of the sub-floor ventilation system and so the full extent of the outbreak could not be determined. Timberwise technicians should be given as much access to and around a property as is possible, to make sure they can complete the most effective and efficient surveys.
The cause of the attack is thought to have been the front path adjoining the main house’s front wall. Dry rot spores are considered omnipresent, and no environment is considered free from them. The spores will germinate and grow in timber with a moisture content of between 20% and 30%. The fine fungal thread (hyphae) digests the cellulose and hemicellulose fraction of the wood but does not attack the structural lignin.
These hyphae remain as brittle matrices which cracks into cubes and differential stresses. Cuboidal cracking is also characteristic of many wet rots and does not automatically indicate the presence of dry rot. Fungal hyphal may clump together into a variety of structures known as mycelia which takes various forms depending on the surrounding conditions. They may fill a humus cavity as a cotton wool like mass or grow across the surface of the timber as a grey or white skin. Active dry rot has a fresh white or greyish appearance. Some hyphae group together to form conducting strands. Their main function is to conduct nutrients through inert non-nutrient material i.e. brickwork, to permit the eventual colonisation of the timbers present.
The relatively impervious outer layer, together with an unusually alkaline tolerance, allows them to survive in the mortar layers of the masonry. In an infested area, the walls may be full of dry rot strands, hence the usual requirement of plaster removal and wall sterilisation. The dry rot fungus may tolerate relatively lower moisture content, and, through this and other facets of its biology, it is potentially capable of considerable destruction.
Recommendations
After the results of the survey, technicians recommended several works that should be undertaken for the property. Firstly, the designated work areas would be prepared by putting down polythene sheets and hardboard to protect from dust and debris.
Wall plaster would be hacked off to the dry rot treatment area, bagging up the residual debris and taking it away from the site. Timber lintels from the basement cellar, ground floor front door and front two rooms, would be removed and replaced using concrete lintels. The front door and cellar door and frames would be removed and boarded up, ready for the client to install new doors.
New treated 200mm x 47mm floor joists and floorboards would be installed. All ends in contact with the masonry will be wrapped in a damp-proof membrane. All new and existing remaining joist ends within the treatment area will be protected with LignaTek fungicidal gel. Finally, a Toxic Box would be formed around the affected area.
Results
Our technicians conducted the survey to the fullest extent possible, despite restrictions within the property, and recommended a professional and well-tested series of works backed by over 50 years of industry experience.
Do You Want to Request a Survey?
Our dedicated and experienced team in Cardiff is ready to talk to you about your options for property preservation. Don’t hesitate to call 02920 290 558 or you can request a survey online.
