Client: Property Developer
Our client, a property developer in Newcastle, tasked Timberwise with designing and installing a basement waterproofing system to protect the property from water ingress. This property was a detached house of red brick construction, and was both unoccupied and unfurnished at the time of our inspection. The weather conditions were light rainfall.
Challenges
The property was undergoing redevelopment at the time of our inspection. This provides both benefits and challenges during an inspection. For example, visiting the property while it’s unoccupied and unfurnished allows our surveyors to fully access all areas of a property without being restricted by decorative features such as floor coverings or fitted units.
However, an active construction site also carries with it significantly more health and safety risks, not only to our surveyors, but also to any other tradesmen on site during our inspection. For example, access was restricted in certain rooms or areas due to the building’s condition.
Being aware of the situation before visiting, our surveyor liaised with our client prior to our visit to ensure the safety of all inhabitants within the building doth during our visit and later during remedial work.
Observations
Our surveyor first attended the property during ongoing renovation works, where they completed an internal inspection of the basement area. The basement had been stripped out prior to inspection, removing a previous waterproofing system.
After a brief external inspection, our surveyor noted that the path levels around the building perimeter had sunk. This suggested potential issues with external drainage or ground stability. This drainage concern may allow for the build-up of moisture behind the basement walls, likely contributing to damp conditions within the property.
During our internal inspection, our surveyor identified evidence of slight but active water ingress and standing water within the basement. This was likely due to the removal of the previous waterproofing system. However, due to its removal, it could not be determined if the previous waterproofing method had developed a defect that had contributed to the internal condition of the basement.
Our surveyor also noted that the internal dividing walls were built directly from the existing floor slab. This might potentially obstruct water flow along the sub-membrane, as it would allow water to build up or dam at the base of the wall. A trial excavation hole in the floor slab of one room also indicated areas of previous repair that would require attention prior to installation to ensure the previous protections were working as intended.
Solutions
In accordance with BS8102:2022, our surveyor designed a basement waterproofing solution that would protect the current basement from water ingress, and allowed for extension in the future to coincide with our client’s plans to develop the property further in future.
As the previous waterproofing system had already been removed, our technicians could begin by preparing the walls and floor slab for the new installation.
They first applied an anti-lime coating to all the concrete walls within the basement. This would prevent lime leaching from the walls and blocking the drainage system, ensuring its longevity.
To combat potential damming at the base of each wall, our technicians bored drainage holes to allow any water ingress to transfer beneath the system once installed. This water would then collect into a drainage channel that was installed into the existing floor slab. Once collected, this would be pumped off site using a sump pump installed into the corner of the basement.
Timberwise considers a Type C waterproofing solution to be the ideal waterproofing solution for underground structures. This creates a habitable space that is protected by several overlapping measures that all work to prevent water ingress into the internal property. They also seek to manage water ingress by allowing it to flow, rather than restricting it. This creates a reduced likelihood of defects forming, a there is reduced hydrostatic pressure behind the wall.
One of these measures is a cement-based cellar tanking, which our technicians installed in the exposed light wells. This would prevent water ingress by creating a waterproof barrier in the walls closest to the external ground surface level.
On the remaining walls and floor slab, our technicians installed a cavity drainage membrane. This is an extendable and removable system which prevents water ingress by directing any internal moisture into a drainage system. This system was ideal for our client as they had plans to extend the basement room in future. If they did, the system could be removed and extended alongside the other building work without compromising the new walls to future damp concerns.
Once the waterproofing system was established, our technicians finalised their work by testing the pumping station and its alarm system to ensure everything was in working order. They also tested the jetting ports to ensure that the drainage channel was clear of any potential debris and that water was running correctly through the system.
Results
Our client was delighted with our work in creating a habitable basement room for their home. They were satisfied that our team worked with their refurbishment team to install a solution that allowed them to extend the system in future, as well as decorate to their desired finish. They were pleased that the system would provide a dry, vapour-proof environment suitable for residential use once the property was finished.
Do You Want Help with a Waterproofing Solution?
Our dedicated and experienced team in Newcastle are ready to talk to you about your options for property preservation. Don’t hesitate to call us on 0191 204 1063, or you can request a survey online.
