Mapei provides a solution for the problem behind spray waterproofing at Bank Station.

Mapei products have been specified for a capacity upgrade project with London Underground at Bank Station. Originally opened in 1900 at Bank junction, the station is served by the Central, Waterloo & City, and Northern lines, as well as the Docklands Light Railway. The upgrade required materials for waterproofing, repairs to the concrete and masonry, as well as a new construction and structural reinforcement.

Due to the detailed specification and the parameters for completion, UTT (Underground Technology Team) Manager for Mapei UK, Steve Price developed and delivered training to operatives who required further technical assistance with the waterproofing system, specifically for the complex installation. Main contractors Dragados agreed that the training provided by Mapei was the key to making the project run smoothly and ensuring the installers were trained to apply and test the new products properly.

Delivery of the training was assisted with expertise from Mapei HQ UTT technical support, a dedicated resource for underground construction. The training, consisting of two modules, was made up of a theory course examining the technical requirements for successful application, followed by a second module – the actual operation of equipment and application through to testing. This approach has resulted in the most successful application of underground waterproofing seen in the UK.

Mapegrout Gunite FSD and the Mapelastic TU System have both been specified for the project, with both sharing the requirement of being packaged in a way that would minimise lifts during use in the tunnel shaft; larger pallets and packaging were more convenient for the station upgrade.  

Mapelastic TU System provided many advantages for the project. The one-component, ready to use membrane offered a clean and neat application with no overspray proving to be useful at Bank Station due to the small passageway adits and tunnels. Due to its pre-mixed formula, the system eliminated dust from the application whilst providing consistency between each layer. The product is available in both green and white to ensure complete coverage of each layer is visible.

One-component, fibre-reinforced cementitious mortar Mapegrout Gunite FSD was applied using a wet spray application, creating a thixotropic consistency for easy application on vertical and overhead surfaces. Its extra fast curing allowed the installers and equipment to move through the tunnels quickly, thus improving the speed of application.