Extension and refurbishment of existing delivery unit at third floor level supported over existing buildings. Due to the tight site and the need to connect to the existing devices it was designed to cantilever over the existing 2 storey engineer building and connect to the existing Labour and delivery unit. Mini- pile foundations where designed between the existing national maternity unit and engineering building a narrow gap of 1200mm. To erect the structure the existing ventilation system needed to be relocated to allow for piling. The existing carpentry workshop was relocated off site and road closures where sought to aid construction and allow for safe construction traffic access. To maximize the useable space a cantilevered section was proposed over the right of way at Holles lane. This involves the entire depth of the 1 storey structure acting as a trusses to stabiles the structure. The design set out to allow the speedy erection of the metal / concrete composite deck. This would reduce erection time and allow for minimal road closures.