Client: Domestic Landlord
Our client, a domestic landlord in Sutton, tasked Timberwise with conducting fungal decay treatment on two adjoining flats after a plumbing leak. This property was a converted semi-detached house of solid brick and external render construction, and was both occupied and unfurnished at the time of our inspection. The weather conditions were sunny during both surveys.
Challenges
Surveying the property presented several access and visibility constraints. Restricted entry to the adjoining flat meant the surveyor could not assess both properties at the same time, while fitted units, stored belongings, and floor coverings limited direct inspection of affected timbers. In Flat 1, parts of the kitchen lounge floor could only be viewed indirectly from the cellar of Flat 2, making it difficult to trace the full extent of the decay.
Observations
Our surveyor initially began by surveying Flat 2, the basement flat. During this inspection, our surveyor identified several areas of damp plaster throughout the basement using an electronic conductivity meter. While only giving an indication of damp, a conductivity meter allows a surveyor to plot damp profiles across a property to diagnose it. In this case, our surveyor believed that the likely culprit was a historic plumbing leak from the flat above.
More pressing, an active outbreak of wet rot fungal decay was identified within the basement floor. In this case, the strain was identified as Cellar Fungus (Coniophora puteana), a common wet rot fungus that attacks timber in damp, poorly ventilated areas. A sub-floor inspection revealed fungal material spread across several floor joists, as well as significant timber decay. It was believed that water from the flat above had leaked into the ceiling, down the wall, and into the floor below, where it created the ideal conditions for wet rot fungus to germinate.
Upon returning to the property after six months, our surveyor then conducted a survey of Flat 1, the ground floor flat just above our where our previous survey had taken place. This survey was limited only to the bedroom and kitchen areas, where the client had also experienced issues relating to previous plumbing issues.
Upon inspecting beneath the kitchen cabinetry and in the bedroom, our surveyor found an additional outbreak of Cellar Fungus on the floorboards. However, upon exposing the chipboard flooring underneath, our surveyor also found evidence of Dry Rot (Serpula Lacrymans), a much hardier species of fungal decay that can travel behind plaster or over masonry to new moisture sources. While wet rot often remains isolated to a single moisture source, dry rot is invasive, and can spread throughout a property if left untreated, including into the ceiling of the flat below. A lack of sub-floor ventilation had exacerbated the situation, preventing the moisture from the previous plumbing leaks from evaporating and escaping the floor void.
Our surveyor also identified structural cracks in the wall plaster in Flat 1, which suggested that the floorboards might have sunk or weakened significantly from both strains of fungal decay. Left untreated, both flats were at serious risk of structural collapse.
Solutions
Having assessed both flats and discussed their concerns with our client, our surveyor designed a treatment plan to eradicate both strains of fungal decay in the two flats, as well as install preventative measures to reduce the likelihood of future recurrence.
To begin, our technicians removed the contaminated floor coverings and kitchen units in flat 1, as well as the affected wall plaster in both flats. This would remove as much fungal material from the properties as possible. Given the extent of the damage, our technicians also installed several props and boards in the Flat 2 basement to support the upstairs floor joists during the timber repairs.
With the wall exposed, our technicians then formed a toxic box (cordon sanitaire) within the masonry. This involves injecting LignaTek fungicidal treatment into small holes, which creates a perimeter that prevents the spread of future fungal outbreaks.
In addition, as one of the walls in Flat 1 had been compromised structurally, our technicians performed crack stitching repairs to restabilise the wall. This involved raking out the mortar joint, and installing a steel rod. This provides additional structural stability to the wall. The rod was then coated with resin and finally a mortar coat to disguise it in the wall.
Between the two flats, our technicians then removed around 4 square metres of floorboards and joists which were too damaged to remain. In their place, our technicians installed in new floorboards and joists, wrapping the ends in a damp proof membrane where they contacted the masonry. The entire floor was then treated with our LignaTek fungicidal solution, eliminating any remaining fungal activity and providing an additional layer of protection against future outbreaks.
Once the wider treatment was completed, our technicians completed the work my replastering the walls with a salt-retardant specification to prevent future moisture build-up within the walls. Finally, they laid a chipboard floor over which our client could redecorate to their preference.
Results
Following treatment, both flats were successfully cleared of wet rot and dry rot fungal decay, with the root causes identified and addressed to minimise the risk of recurrence. Structural integrity was restored through careful timber replacement, crack stitching, and specialist masonry treatments, while preventative measures such as fungicidal barriers, damp proof membranes, and salt-retardant replastering were installed. With floors and walls safely reinstated, the client was able to redecorate with confidence and return both properties to normal use.
Do You Want Help with a Fungal Decay Solution?
Our dedicated and experienced team in South London are ready to talk to you about your options for property preservation. Don’t hesitate to call us on 0208 226 4168, or you can request a survey online.
