This mixed-use retail and hotel development was designed in structural steel for the ground and first floors and pre-fabricated timber frame for the storeys above. Piled foundations support an insitu reinforced concrete suspended ground floor slab. Pile caps and ground beams are formed integrally with the ground floor slab to keep excavation depths to a minimum to reduce volumes of cut material taken off site. Surface water run-off from the roof and external paving is collected and stored in an insitu reinforced concrete tank located beneath one of the retail units. This piled suspended sub-structure tank is located within available space between pile caps and ground beams, with the lid of the tank forming the ground floor slab of the retail unit. Volumes of surface water are restricted to agreed rates before being discharged to the adjacent public system.