DEVELOPERS REBUILDING the Trafalgar Hotel in central London had to retain the original facade and character of the building.
Underground vaults were also retained but the entire underground area was redesigned to house leisure facilities as well as the kitchen and restaurant.
Subcontractor Mitchellson Formwork recommended using a waterproofing system but pile head foundations and walls made installing a membrane waterproofing system impractical.
Applying a membrane around these intrusions would have been difficult, time consuming and could have run the risk of leaking at the overlapping sections.
Instead Mitchellson used Pudlo concentrated waterproofing powder in all below-ground work, including the basement slab, exterior wall and retaining wall.
The concrete admixture sufficiently changes the properties of concrete to make it completely water resistant. Manufacturer David Ball Group says the material is particularly useful on sites where there are pile heads and other protrusions.