Fast-track roofs for Network Rail
The Corus Hi-Point off-site modular roofing system has been used for the fast-track construction of the first new railway station to be built in London since the 1930’s. Eastfields Station near Mitcham in south London was commissioned by Network Rail who worked in close collaboration with their designers, Jabcobs Babtie and Corus Infrastructure Services.
Main contractor, Dean & Dyball Rail appointed Gable Rail to install all the Corus Hi-Point roofs on the station building, platform canopies, rail footbridge and lift shafts. Dean & Dyball’s Divisional Manager, Craig Watt says, “The Hi-Point off-site system enabled the roofs to be installed quickly, safely and to our precise programme. This often involved evening deliveries in train-free ‘possession’ hours for safety reasons. With a tightly constrained location such as Eastfields, these ‘just-in-time’ deliveries meant the site never became cluttered with roofing components and packaging because the Hi-Point roofs were craned straight from lorry to roof.”
Just two Hi-Point ‘warm roof’ modules, each size 3.75 x 12.5 metres long, were required to create the low-pitched pyramid roof that covers the station building. Manufactured in the factory, these ‘warm roof’ modules were constructed to achieve a ‘U’ value of 0.25 W/m²K. Comprising a lightweight steel frame (which also creates the roof pitch) the modules were delivered ready for quick installation complete with liner deck, vapour control layer, thermal insulation, flashings, insulated walkable gutters and topped with Kalzip aluminium standing seam roof sheets on secret direct from the lorry up to roof level and affixed to the supporting structural steel where the final Kalzip sheet was installed to join the two roof
A similar ‘just-in-time’ delivery and installation procedure was also employed for the Hi-Point ‘cold roof’ cassettes used on all the external areas of Eastfields Station. These cassettes are of a simpler design comprising a lightweight steel frame with secret fix clips affixed to the upper side to take the single skin mono-pitched Kalzip roof sheets which are zipped to the adjacent unit when in situ.
These repeatable ‘cold roof’ cassettes were used for the main station building’s low pitched canopy roof which shares the central ‘warm roof’ gutter and drainage system. The 29 metre long cantilevered platform canopy was also created using 4 identical cassettes, each size 1.9 x 6.0 metres long with shorter units at each end.
Each side of the gull-wing footbridge roof over the rail line comprises 4 mono-pitched single skin pre-cambered cassettes which drain into a central gutter linked at right angles to the gutters of larger mono-pitched roofs abutting the lift shaft towers at each end. Two single skin mono-pitched cassettes which drain into their own central gutter were required for each of the lift shaft tower roofs.
Gable Rail completed all the station’s single skin ‘cold roofs / canopies’ by site-fitting a series of soffit panels, colour matching fascias and bull-nose flashings. Due to the more complex, stepped nature of the footbridge stairways that run from the platforms up to the rail footbridge, it was more cost-effective for Gable to install traditional single skin Kalzip roofs with cranked sections where necessary.
Greenhithe Station, a similar but slightly larger development at Dartford, Kent has also been built for Network Rail using the same Corus Hi-Point off-site modular roof system. A further station is currently in the process of being built at Corby in Northamptonshire.
Corus Hi-Point off-site roofing system is ideal where repeatable ‘custom-designed’ roofing solutions are required. The modules can include any combination of mono-pitch, duo-pitch and barrel vault roofs incorporating a roof build-up specification to suit the individual project or series of similar projects requiring repeatable design elements.