Client: Domestic
Our client, a homeowner in London, tasked Timberwise with conducting widespread dry rot treatment on their property after a plumbing leak. This property was a semi-detached house of solid brick construction, and was both occupied and furnished at the time of our inspection. The weather conditions were overcast but dry.
Observations
Our surveyor began by conducting an external examination of the property. During this investigation, our surveyor identified several areas of damp staining on the masonry of both the front and rear of the property. Our surveyor believed that this was likely due to faulty rainwater foods. After discussing with our client, they revealed that the front rainwater pipes and guttering had been repaired previously.
In addition, it was not possible to establish if there was a damp proof course (DPC) present at the property. A DPC is a waterproof barrier that prevents moisture ingress from rising through a wall and appearing inside the property. If one wasn’t present, it was likely that rising damp would be a contributing factor to the internal condition of the property.
To corroborate this, our surveyor began their internal investigation by plotting the ground floor walls with an electronic conductivity meter. This tool detects the presence of moisture within plaster or masonry. While it’s ideal use is to measure the true moisture content of timber, it can still provide an indication of a damp issue. After assessing the walls, elevated moisture levels were identified on both the front and rear elevations.
However, the most visible cause for concern was within the front reception room, where a case of dry rot fungal decay (Serpula lacrymans) was identified within a decorative timber beam installed on the wall. Dry rot is an invasive species of fungus, capable of spreading along walls or behind plaster to find new moisture sources, even after a damp or leak problem has been successfully repaired. As there were several cosmetic cracks in the room’s coving, our surveyor suspected that the fungus had spread into the ceiling.
As the hyphae appeared established and deep-seated, our surveyor recommended a deeper inspection underneath the floorboards to identify the full spread of the rot. With the blessing of our client, our surveyor removed several floorboards in the ground floor rooms.
This inspection confirmed our surveyor’s fears, and several other fungal outbreaks were identified in the front rooms on both the ground and upper floors, as well as the rear shower room. The shower room was the worst affected, and was believed to be the site of the initial outbreak due to a prior plumbing leak. The damage was so extensive, that the shower tray had sunk, suggesting that the timber floorboards had succumbed to significant fungal decay.
Notably, the dry rot was also identified in a bressumer beam in the upstairs room. A large load-bearing beam, the bressumer beam is a key structural component in expansive floors, often used to provide support above a bay window or fireplace. More alarmingly, a further inspection in the shower room revealed that the internal brick wall between the shower room and hot water cupboard was suspended on a timber floor rather than a structural base.
Solutions
Without immediate remedial action, our surveyor believed that the structural strength of the property was at risk of collapse, especially if the dry rot outbreak was left untreated. With the agreement of our client, our team set to work repairing the property.
To begin, our technicians prepared the property for treatment by removing the sunken shower tray, lino, and floorboards in the bathroom. In addition, they stripped away the contaminated wall plaster alongside any organic material. Finally, as there was a danger of structural collapse, our technicians also installed several support props in the ground floor room to support the ceiling joists above and allow for repairs on the bressummer beam.
Once the preparation work had concluded, our technicians began the wider treatment plan. First, our technicians installed a DryTek DPC system into the affected walls after confirming that there was no DPC currently installed. They achieved this by drilling into the mortar joints at regular intervals, which they then used to inject a DPC chemical cream. Once dry, this would create a fresh waterproof barrier to prevent future rising damp concerns. In the rear shower room, the floor void was also blocked up underneath the dividing wall to provide additional structural support.
Once the DPC was completed, our technicians next installed measures to prevent future dry rot outbreaks. To do this, they first created a Toxic Box, a chemical barrier within the affected walls. This was achieved by drilling into the wall at regular intervals, and then injecting a fungicidal gel directly into each hole. This would prevent any fungal decay from spreading beyond the toxic box, preventing any future widescale damage.
Next, the team began conducting timber repairs in all rooms. This involved cutting back any severely decayed joists, wall plates, and sections of the bressummer beam in the ceiling. In each case, the timbers were replaced with new pre-treated sections, which were then bolted onto the original timbers. On the wall plates, the new timbers were further isolated from the masonry by installing a damp proof membrane, which would prevent moisture from accessing the fresh timbers. The timbers were all then sprayed with a chemical dry rot treatment to provide additional protection against fungal decay.
Once the wider repair work was completed, our technicians completed the treatment plan by replastering with DryTek salt retardant specification plaster. This would prevent hygroscopic salt migration. Once dry, the walls and ceiling were then skimmed, leaving them in a ready state for decoration once the plaster was fully dried out.
Results
Our team’s treatment plan successfully removed and chemically treated a widespread outbreak of dry rot fungal growth across multiple rooms and floor. In addition, our technicians also completed wider structural support work in both the masonry and timber components of the property, preventing the possibility of structural collapse. Our client was delighted with our team’s efforts, and was provided peace of mind that their 20-year guarantee would remedy any future dry rot issues should they arise.
Do You Want Help with a Dry Rot Solution?
Our dedicated and experienced team in North London are ready to talk to you about your options for property preservation. Don’t hesitate to call us on 020 8226 6486, or you can request a survey online.
