The American School campus in St Johns Wood is on a compact site with little room for expansion. A concept for a new pool and fitness centre was designed by ORMS Architecture. This enabled the school to receive first class facilities built underground; just below the playground and just above the Jubilee line.
This project was planned in intricate detail allowing only sections of the basement to be constructed at a time to avoid any disturbance to the Jubilee line and the surrounding sub soils. The risk involved with excavating so close to a tube line meant only certain amounts of sub soil could be excavated at once. FIS Construction Products designed a waterproofing system which would provide a Grade Three basement in accordance with BS8102:2009, meet the contractors budget and be practical for installation with small concrete pours.
A waterproof concrete system with Hydrophilic waterbars was developed. This meant that the contractor did not have the concern of ensuring a membrane was properly connected to the membrane under the previous pour.