The work to create new office space was awarded to a Costain/Laing O’Rourke joint venture in May 2007 as part of the £400 million revamp of the station, with a target cost of £30 million.
But this has escalated to £60 million, with the cost of preserving original features taking up most of the increase.
The rail operator and contractors have been meeting with conservation body English Heritage every two weeks to ensure the 250 m long building retains its Victorian characteristics, using the best methods and materials.
Network Rail King’s Cross programme director Ian Fry told Construction News: “It’s beyond our original budget but it has all been worthwhile.
This is an important long-term restoration project and we’ve improved how we’re doing things. We’ve kept and restored all the original fireplaces, windows, doors and skirting boards.
“Many have been repainted and repaired. We’ve installed secondary glazing inside all the original windows to make sure the building is up to modern energy efficiency standards.”
The job also included building a new southern office entrance, M&E work, a new mezzanine floor and building three new plant rooms.
The original eastern range contract also included the construction of platform Y - a new 300 m platform to the eastern side of platform 1 at King’s Cross. But the job will now be let separately in early spring next year.
Work on the eastern range is scheduled to finish next autumn and will see rail staff from Network Rail and the train operators, including National Express, which runs trains on the flagship East Coast Main Line, switch from premises on the other side of the station on the western range.
Other work at the station will involve building a new concourse. Taylor Woodrow is currently working on the stage 1 design for the concourse, which also includes the rebuilding of the western range, with enabling works set to start next month.
The main £125 million contract at King’s Cross is still in negotiations. Network Rail hopes to make an appointment in the next three months.
Restoring the eastern range
• Removal of damaged original roof slates and sections of roof affected by construction of new plant rooms. Target to re-use 35 per cent of the original roof slates
• Demolish and rebuild six chimneys to allow construction of the northern plant room
• Replace 338 stone sills with new hand-tooled sills
• Removal and reinstatement of 260 m long section of stone coping at roof level to facilitate construction of new gutter for surface runoff.
• Coping stone to be fitted with new safety rail/balustrade along entire length
Analysis: We’re building on our industrial best
By Clare Brady
King’s Cross Central is arguably the most important regeneration project in London.
The redevelopment of former railway lands aims to create a vibrant new quarter for the city.
English Heritage has, and will, continue to work with the key partners - Argent, Network Rail and Camden Council - on this highly ambitious and complex project.
The history of the area and the listed status of many of the buildings within the site can be seen to be providing opportunities, rather than hindrances, to development.
English Heritage has worked alongside the developers in the past decade to secure appropriate new uses for the listed buildings on the site alongside sensitive redevelopment of the surrounding lands.
All partners agree that a form of development which builds upon the best of our industrial past to help create a place of character for the future is, undeniably, ambitious but also desirable and achievable.
Clare Brady is senior historic buildings and areas advisor for English Heritage