Basement Waterproofing and Combined Protection
'Combined Protection' is a section within BS8102 Code of practice for protection of below ground structures against water ingress; it advises that designers consider the use of two forms of waterproofing, either where there are aggressive site conditions (it's a wet one), or the consequences of failure are high (few pennies required if it goes wrong).
By James Hockey
This approach has been widely adopted in residential (specifically habitable space) new-build because the consequences of issue historically have been particularly costly. The best data that we have on this is that which was published by the NHBC in 2014, in relation to their claims spend which was £20.5 million pounds over an eight year period (£13k per day).
It's completely understandable why 'combined protection' / dual forms of waterproofing has been widely adopted in residential, but there are three forms of waterproofing to choose from, so what to select and specifically why do we and others always include cavity drainage?
Firstly, to cover the basics, these 'types' are defined within BS8102 as:
Type A, which is 'barrier tanking', this is where a specific barrier material is installed on or within the structure, to block water out.
Type B, is 'structurally integral protection', essentially where the structure itself is the barrier to block water out - typically reinforced concrete but can also include steel sheet piling.
Type C, is 'drained protection' - commonly referred to as 'cavity drainage'. Any water ingress is collected, removed, and isolated from the interior with vapour barrier membranes.
We provide a single point of responsibility protecting all stakeholders.
We take full accountability for the waterproofing process, serving as a single point of responsibility to ensure seamless coordination and execution. This approach protects all stakeholders by minimising risk, eliminating communication gaps, and ensuring the highest standards of quality and reliability throughout the project.
Find out more
