Client: Property developer
Our client, a property developer in London, contacted Timberwise to install damp proofing measures in their home. This property was a terraced house of solid brick construction, and was partially occupied and furnished during our inspection. The weather conditions were dry and sunny.
Observations
Our surveyor began by conducting an external investigation of the property. During this investigation, our surveyor found no evidence of a Damp Proof Course (DPC) within the exterior wall. This is not uncommon in properties of this age, however, the lack of a DPC can allow damp to rise through the natural capillaries within brickwork. This damp then often appears as visible tide marks on the interior wall plaster or wallpaper.
Another potential issue was identified with the external render. This was found to be in contact with the floor outside. This can allow groundwater to bridge over a DPC and into the wall. In this case a DPC wasn’t present, but the render would still be allowing additional moisture to build up in the walls over time.
Internally, our surveyor identified several areas of visible damp plaster to the front elevation and party walls throughout the property. After using an electronic conductivity meter on the walls to assess their ambient moisture levels, our surveyor concluded that the lack of a DPC and bridging plaster outside the property had caused areas of rising damp to form.
Rising damp had also allowed historic salts to accumulate within the plaster, encouraging atmospheric moisture to continue returning to the wall. Over time, these two contributors of damp had caused the plaster to fail and wallpaper to peel in some areas of the property.
In addition to the ground floor rooms, our surveyor was also asked to inspect two under pavement vaults in the cellar of this property. Like the above ground rooms, there were signs of failed plaster within the ceiling and walls. This was believed to be caused by penetrating damp, most likely from groundwater behind the wall seeping through a defect into the room itself.
Solutions
After consulting with our client about the best solution for their property, our surveyor designed a treatment plan that would not only treat the sources of moisture ingress on the ground floor, but would also transform the basement vaults into habitable spaces that our client could use for more than storage.
Externally, our technicians first removed the bridging render from the base of the wall. This would prevent moisture from being able to rise through the wall so readily. Once cleared, our technicians then installed a chemical DPC system. This involved drilling into the mortar joint of the wall at regular intervals, just above ground level.
In each hole, a chemical gel was injected, which would turn into a waterproof barrier once hardened. This would additionally prevent water from rising through the capillaries in the masonry. As a final measure, our technicians also injected a vertical barrier into the party wall to prevent ingress from the neighbouring properties.
Internally, our technicians continued the installation of the DPC, removing any salt contaminated plaster as they went. Once the DPC was installed, each wall was replastered with a salt retardant plaster finish, preventing future salts from infesting the plaster and encourage atmospheric moisture to settle into the wall.
Finally, our technicians tackled the basement vaults. To combat the penetrating damp, they first cleared the salt contaminated plaster as they had upstairs. However, a chemical DPC would not prevent damp from penetrating into the vault. Instead, our team installed a mesh membrane to the vault ceiling, walls, and floor. This would not prevent moisture ingress, but instead, deflect any water ingress off the membrane.
At the base of the wall, a perimeter drainage channel system was dug at the base of each wall. This would collect any water ingress from the membrane, to be pumped off site by a sump pump. Once installed, the basement could then be decorated to our client’s specification.
Results
Our client was delighted in the assistance of our team in protecting their property from future damp ingress. They were also pleased that not only were both damp issues resolved successfully, but their downstairs storage area could now be used as a habitable area, extending the footprint of their property.
As a show of appreciation for our team’s efforts, our client invited out surveyor back to their property a year after our work had concluded. The basement and ground floor of the property had since been converted into a new two-bedroom flat, with a large bathroom and front reception room.
Do You Want Help with a Damp Proofing 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.
