Application of Decorative Render to 8,500m² of Platform Tunnels
Background
Travelling via the Heathrow Express high-speed rail link is the fastest means of journeying between Central London and Heathrow Airport. Taking just 15 minutes from Paddington Station to Heathrow Airport, 16,000 passengers travel via the Heathrow Express daily and since the service was launched in June 1998, it has carried over 60 million people. The service runs from Paddington following the Great Western Line for 12 miles where it enters a five mile tunnel near Hayes. From here it continues under the airport to two stations, one serving Terminals 1, 2 and 3 and a second four miles away beneath Terminal 4.
Upon completion of the tunnelling works in early 1997, trial works were carried out for the application of a decorative render to the platform tunnels at the Heathrow Express rail link at Terminal 4. The client was seeking an aesthetic, protective render that would match the existing decorative precast GRC wall panels and remain maintenance-free during its design life.
The Solution
A bespoke Flexcrete product was devised for this prestigious project, comprising Monolevel 844SP modified with a blend of selected micas from international sources to produce a highly striking sparkle effect, quite unlike the drab finishes normally associated with protective renders.
Monolevel 844SP is an engineering quality fairing coat which provides a protective waterproof and anti-carbonation finish. CE marked in accordance with BS EN 1504 and approved by London Underground, the modified version was applied to the curved concrete walls to both platforms, the pedestrians tunnels and to concourse areas above.
The render was applied at a thickness of 2-3mm by hand and was finished with a damp sponge to fully reveal the translucent mica inclusions. Within the cross tunnels and concourse areas dummy joints were introduced to provide a continuous finish matching the newly installed decorative GRC wall panels. Over 8,500m² of modified Monolevel 844SP was applied over a six month period.
Client
Laing Baily Joint Venture
Project Profile - Heathrow Express