Aggregate Industries’ Lytag proves the ultimate concrete solution for the £250m redevelopment of 100 Liverpool Street


The Background

As part of the wider Broadgate campus adjacent to Liverpool Street station, the high-end redevelopment strips the original building back to its structural frame, demolishing 50% of it and rebuilding new infills in structural steel with the addition of three new floors to create modern, mixed-use space. Once complete, it will provide 520,000 sq ft of office and retail space and a new rooftop terrace offering outstanding views over the city.

The Problem

For main contractor, Sir Robert McAlpine, a key requirement of the project was to source a concrete solution which would enable more floors to be cast without compromising the dead load of the overall structure.

The Solution

Aggregate Industries’ Lytag, a highly innovative lightweight aggregate solution, was used to effectively reduce the composite deck concrete slab load by approximately 25% over normal weight control while offering the same level structural performance - enabling 100 Liverpool Street to – literally - reach new heights.

Made from secondary aggregate, Lytag also offers a much more environmentally friendly alternative to standard concrete as thanks to its unique properties, it can help to significantly reduce the amount of material required on a project, along with the associated carbon emission produced in delivery.

In total, Aggregate Industries, working with its specialist London Concrete unit, has supplied 5000m3 of Lytag to the project, with the building featuring an array of sustainable features that complement the significantly reduced carbon footprint. As a result, 100 Liverpool Street is expected to receive an Excellent rating in BREEAM.

Barry Mellor, Commercial and Technical Manager for Lytag, comments: “This project wouldn’t have been structurally or architecturally possible without Lytag and its unrivalled capabilities. It was also instrumental in helping the building to achieve an Excellent rating in BREEAM.”


Project details

  • High-rise buildings

  • Sir Robert McAlpine

    • High-end redevelopment
    • Highly innovative lightweight aggregate solution
    • Environmentally friendly alternative
    • Supplied 5000m3 of Lytag to the project

“Lytag is a fantastic product which has enabled us to realise our vision for the refurbishment of 100 Liverpool Street and create something architecturally and sustainably outstanding.”

Peter Watts, Project Manager at Sir Robert McAlpine