Project Location: King’s Cross Station, London

Posted on in the category Structural Waterproofing and Tanking, Waterproofing of Roofs & Other Deck Areas, Civil Engineering & Infrastructure, Waterproof Flooring Solutions.

Waterproofing System for Concrete Roof at King’s Cross Station

Waterproofing of reinforced concrete roof over a plant room.


Opened in 1852, King’s Cross Station now handles 47 million passengers a year and is famous as the departure point for the Hogworts’ Express in the Harry Potter films.

To prepare for the 2012 Olympics, £400m has been allocated for upgrading, with the Eastern Range being converted into offices for 400 staff utilising much of the original structure. Located under the original roof, newly constructed plant rooms required a permanent waterproofing system.

The Solution

JV Contractor Laing O’Rourke Costain chose Cementitious Coating 851 following its successful application over green concrete at Heathrow T5. After pouring the slab, it was left to cure overnight before preparing with a stiff brush and thorough soaking. To prevent outgassing, Cemprotec EF Primer was applied, a fillet was installed around the perimeter with Fastfill and Cementitious Coating 851 was laid at 2mm thickness. Cemprotec EF Grit was cast into the surface to give a slip resistant finish. Within the space of 4 days, the slab was cast and waterproofing completed in record time, with heavy machinery installed just a few days later.


Network Rail


Laing O’Rourke / Costain jv