Client: Property Management Company
Our client, a property management company, instructed Timberwise to inspect a property in Exeter to determine the presence and extent of wood rot fungal decay within the kitchen and surrounding areas. The inspection was carried out following initial building works which revealed additional dry rot beyond the originally exposed areas. This property was a listed mid-terraced house of solid brick construction and was occupied and fully furnished at the time of inspection. Weather conditions during the survey were dry.
Challenges
During our inspection, access was restricted to just the areas showing evidence of dry rot fungal decay. This is a common challenge during surveys of this nature. However, limiting the scope of a survey does risk not catching every part of a dry rot infestation. This is because dry rot is especially resistant, allowing it to traverse long distances in search of additional moisture sources, even over or through masonry, mortar, or plaster. This is evident when further pockets of dry rot were exposed during renovation work in the property. Finding any evidence to suggest the full spread of fungal decay would require further supplementary exploration.
Observations
After a thorough internal examination, our surveyor identified several defects within the property. Primarily, dry rot fungus (Serpula lacrymans) had been found and identified throughout the perimeter walls of the property, notably in the timbers supporting the metal stud walls. These timbers had been covered with a damp proof membrane (DPM), a popular solution used in its basement waterproofing work or where significant water ingress is a factor, such as in high flood risk areas.
However, this is not the ideal application of this solution, as applying a DPM to wood often causes it to sweat in warmer weather. In addition, while this membrane had been installed on top of the timbers, it was not installed underneath, allowing moisture to easily ingress into the beams where they were in contact with the floor.
A further inspection also revealed that high ground levels outside the property had likely contributed to lateral damp penetration within the property. These combined factors created the perfect breeding ground for dry rot fungus to thrive.
As the investigation continued, evidence suggested that the infestation was not just present in the wall timbers. A close inspection of the floor underneath the floorboards revealed significant fungal spread beneath the floorboards and into concealed wall and floor zones.
Finally, in addition to the dry rot, areas of wet rot were identified in the front left and left elevation stud wall timbers. These also acted as support for the stud walls and were at risk of collapse if left untreated.
What are the Differences Between Wet Rot and Dry Rot?
Wet Rot and Dry Rot are two different types of fungal decay that attack moisture-rich wood. One can often be misdiagnosed with the other, but there are some tell-tale signs you can look for;
- Wet Rot requires a constant source of moisture, whether this is a leak, penetrating damp, or rising damp from high water levels. Dry Rot will often spread towards new sources of moisture, even over plaster or masonry.
- Wet Rot Fungus needs a higher moisture content (50%) when compared with Dry Rot (20%) to achieve its ideal germination environment.
- Wet Rot Fungus will cease to grow when its moisture source depletes, while Dry Rot can lay dormant until conditions improve.
Our blog, Identifying the Differences between Wet rot and Dry rot, goes into further detail about how to identify each case of rot, and what treatments are available.
Solutions
In most rot cases, remediation is only possible through complete replacement of any timbers within the affected areas of the property. This was the solution our surveyor recommended in this case, and after an agreement was reached with our client, our technicians began work on the property.
Our team began work by replacing not only the Dry Rot-affected wall timbers, but also the Wet Rot-affected timbers in other areas of the property. This restored the structural integrity of the property, while removing any fruiting bodies from the dry rot fungus to ensure it could not spread again once treatment was completed.
Once the timbers were reinstated, our technicians also installed a new damp proof membrane. However, this time the DPM was installed to the ideal specification, ensuring the timbers were not in direct contact with the damp masonry or floor. This ensured that water could not find its way into the timbers in future, preventing further decay. A chipboard floor was then installed over the membrane to protect it from any puncture damage from future flooring installations such as carpet or laminate.
To finalise the rot treatment solution, our technicians treated the remaining affected areas, including the exterior door, with fungicidal gel. This gel would eliminate any remaining trace of fungal spores and was applied to any areas where rot damage was not severe and the wood could be restored to its original strength.
However, one final measure was required: Fixing the source of water that caused fungal decay in the first instance. To combat future moisture ingress, our technicians also installed our DryTek Damp Proof Course (DPC) System to the exterior walls. This involved injecting a water-resistant gel into the mortar joints in the wall just above floor level. This gel hardens into an impermeable barrier, ensuring that future damp could not rise into the walls or floor in future. These holes were then filled, and would be covered my the skirting board once it was refitted to the wall.
Results
Our client was overjoyed that our surveyor identified the extent of dry and wet rot within the property, as well as the causes of moisture ingress. They were also thankful to our technicians, who provided a full programme of remedial works that guaranteed the protection of our client’s property from future rot outbreaks.
Do You Want Help With a Dry Rot or Damp Solution?
Our dedicated and experienced team in Exeter are ready to talk to you about your options for property preservation. Don’t hesitate to call us on 01392 300 226, or you can request a survey online.
