Case Study / Waterproofing

Luxury Apartment Waterproofing, Surrey

Ensuring a dry and habitable basement

Nomad Developments, a prominent property development firm, enlisted our expertise to devise a comprehensive waterproofing solution for an exclusive collection of nine luxury apartments in Surrey.

These meticulously designed new builds required a robust and reliable waterproofing strategy to ensure their longevity and structural integrity.

Our involvement began at the pre-construction phase, allowing us to collaborate closely with the entire design team. This early integration was crucial, as it enabled us to provide valuable insights and recommendations on the best practices for incorporating waterproofing measures into the building's construction.

By working together from the outset, we ensured that all stakeholders were well-informed and aligned on the optimal approach to achieving a watertight structure.

Method

Our experienced surveyor meticulously assessed the project details and collaborated closely with the client to ensure a robust and effective waterproofing strategy.

According to BS8102:2022 (Protection of below ground structures against water ingress - code of practice), it is recommended to consider two forms of waterproofing where the risk of failure is unacceptable. Given that this project involved a dry, habitable environment (Grade 3 environment in BS8102:2022), any water ingress would be unacceptable. Therefore, two forms of waterproofing were essential.

Primary Protection: Crystalcoat System. We selected our Crystalcoat system as the first line of defense. This system was applied to the retaining and ground-bearing elements of the building, providing a durable and reliable barrier against water ingress.
Secondary Protection: Type C Cavity Drain System. The most critical component of our waterproofing solution was the Type C Cavity Drain system. This maintainable and guaranteeable system ensures long-term protection. For this project, we employed a gravity drainage approach, eliminating the need for sumps and pumps. The cavity drain system was designed to drain into the surface water drainage system via a 110mm underground pipe through the slab.

To prevent the possibility of reverse flooding, it was crucial to ensure that the drainage system would not surcharge or back up. In cases where there is any doubt about the gravity-fed drainage system, the use of sumps and pumps is recommended.

Additionally, we paid special attention to the detailing at the top of the retaining wall, a commonly overlooked area that can lead to significant claims with warranty providers such as NHBC.

For any new build basement, it is essential to plan for service entry points for utilities such as gas, electricity, and water. We incorporated gaskets into the original plans to keep these entry points dry and secure.

Results

MacLennan successfully installed a fully compliant waterproofing system for the lower ground floor of these luxury apartments. The project was executed within the agreed time frames and budget, demonstrating our commitment to efficiency and client satisfaction.

Our comprehensive approach ensured that the lower ground floor remained free from water ingress, providing a safe and habitable environment for future residents.

Furthermore, MacLennan guaranteed the work, providing peace of mind to the client.

The project was covered by our £10 million Professional Indemnity (PI) insurance, underscoring our confidence in the quality and reliability of our solutions.