Client: Domestic
Our client, a homeowner in Portsmouth, contacted Timberwise to discuss a case of rising damp within their property, believed to be contributing to an influx of wet rot fungal decay. This property was an end-terrace of solid brick construction and was both occupied and furnished at the time of our inspection. The weather was cold and damp, and our survey was not limited to any specific areas of the property.
Observations
After a brief external investigation, our surveyor noted a lack of adequate sub-floor ventilation at the front of the property. Not only were there a shortage of air bricks, but these were also partially blocked, both by raised floor levels and by vegetation. It was concluded that previous groundworks had caused the floor levels to rise around the air bricks, reducing air flow and increasing the risk of fungal decay.
This concern was further compounded by a lack of air bricks in the rear elevation of the property. The rear interior floors in the property were of a solid construction, meaning they did not require air bricks. However, without enough air bricks throughout the property, it can be difficult for air to circulate and remove any pent-up moisture from the sub-floor void before it can cause issues.
Our surveyor also attempted to locate an existing Damp Proof Course (DPC) to confirm if it was function correctly. However, the external walls were coated in render, which prevented the identification of any existing DPC. The render was found to be in good condition and not in contact with the exterior floor, which can cause moisture to bridge over a DPC if one is already present. Our Damp Proof Course page has further information on what a DPC is and how you can identify if you have one in your home.
Inside the property, moisture profiles were plotted using a conductivity meter around the property, including at the front entrance, side elevations, and the sub-floor. Conductivity meters are non-destructive and only give an indication of moisture content on masonry but a true reading on timber. These readings indicated the presence of rising damp within the walls, most likely due to the absence of a working DPC. With considerable readings coming from the lower walls and the floor, our surveyor suggested removing some of the chipboard floor sections to gain access to the floor timbers and sub-floor void, to which our client agreed.
After removing five chipboard sections of floor and exposing the timber flooring and sub-floor void, out surveyor’s suspicions were confirmed. After taking additional moisture readings, excessive moisture levels were evident in the sub-floor void. Normal moisture levels in any timber construction materials should be between 15-19%. However, the timbers in the sub-floor were found to be between 31-48% moisture content, making them the ideal habitat for wet rot to thrive.
A cause for the moisture content was soon identified: Not only were the timbers in direct contact with the adjoining masonry, but they were found to be poorly constructed and isolated from the brickwork in the supporting wall. This not only meant that moisture could easily ingress through the exterior walls and into the timbers, but also that the floor could be at risk of collapse through not being correctly supported.
A further investigation beneath the floorboards also confirmed the presence of Cellar Fungus (Coniophora puteana), a wet rot fungus that attacks moist timbers and weakens their structure. Wet Rot Fungus can’t spread further than moisture allows but given the heightened damp levels within the sub-floor void, it was easy for the fungus to spread among the floorboards and joists.
With the combined threat of wet rot and the floor’s structural integrity called into question, it was apparent that swift repair work be taken to restore the floor and protect it from future rot outbreaks.
Work to be done by Timberwise
During wet rot treatment, the only remediation available to cure an existing infestation is to entirely remove any infested timbers. Wet rot can structurally weaken any joinery, so just treating existing decayed timbers with fungicidal chemicals would not restore their integrity. Instead, our surveyor recommended removing 20m2 of chipboard flooring and an additional 60m of decayed timber joists, replacing them with new timbers and cable flooring. These new timbers and any timbers remaining would all be treated to provide a barrier of resistance against further fungi or rot attacks.
In addition, our team would install new air vents to the rear of the property. This would encourage air to flow under the building and allow for moisture to be ventilated more easily from the sub-floor void.
Finally, our surveyor made allowances to prevent any further moisture ingress. First, he recommended removing the existing wall plaster, not only to install a new DryTek DPC System, but also to replace any historic salts embedded in the walls with a salt-retardant material. This would ensure that moisture would not be able to rise through the wall in future and cause further damage.
Results
Our client was pleased with the attentiveness shown by our surveyor during their visit and appreciated their vigilance in both locating and confirming the extent of the wet rot infestation within their home. They now had peace of mind that not only would their wet rot issue be resolved, but that their floor would be both restored and improved afterwards, ensuring the structural stability of their living spaces. With over 50 years of industry experience, our PCA-qualified surveyors delivered a reliable and effective treatment plan.
Do You Want Help with a Rising Damp Solution?
Our dedicated and experienced team in Fareham are ready to talk to you about your options for property preservation. Don’t hesitate to call us on 01329 339 176, or you can request a survey online.
