The construction of Ilona Rose House, London

Ilona Rose House’s four-storey basement was the key challenge for our team, not only because of its depth, but also because it combines a steel frame with concrete slabs, calling for careful coordination between steel and concrete subcontractors in a confined space.

Like many projects in central London, the Ilona Rose House site is surrounded by third-party assets that we needed to protect and work around. An Underground line and a Thames Water sewer ran metres from the site boundary, and there is a Crossrail I site to the north, as well as a planned Crossrail II site to the west.

Additionally, one of our neighbouring buildings, the House of St Barnabas, contains a richly decorated chapel dating from the 1860s. As part of the measures implemented to protect the chapel, and our other neighbours, McAlpine Design Group were involved in developing a removal sequence that both saved money and improved the overall programme.

The project includes multiple façade types, including the striking pale pink cladding on the upper floors of the building. Our team identified that the original ultra-high performance concrete panels would be heavy to lift, and as a new technology presented a risk to the project.

We worked with the client and the architect to identify the best alternative, like a pressed metal panel and finalising on a GRC which presented a significant value engineering opportunity.

The four-storey basement provided a technical challenge for the team, not only because of its depth, but also because it combines a steel frame with concrete slabs, calling for careful coordination between steel and concrete subcontractors in a confined space. These engineering challenges were an opportunity to leverage our digital construction expertise.

Our team drove the adoption of digital technology, showcasing techniques and processes to minimise risks. They worked in close collaboration with our client Soho Estates to optimise the benefits to the project, as well as the Architect and design teams, who were new to aspects of this technology.

With the assistance of McAlpine Design Group, we were able to develop a Revit model which was then used by the consultant and trade teams to coordinate the design throughout RIBA stage 5.

We took the information provided in the model and conducted detailed clash detection and coordination with the permanent works, reducing our risk.

Further use of the model allowed for quick decision turnaround from the client team, and the ability for the team to answer questions and find solutions during times when a physical on-site presence was restricted due to the Covid pandemic. Early engagement with the Mechanical, Electrical, and Plumbing trades with the model was a major factor in the success of the project. Having buy-in before they started on site reduced resources and delays in critical phases of the project.

The combination of digital technology, pro-active collaboration, and a desire from the outset to set a high standard of engineering excellence demonstrates what Sir Robert McAlpine projects can achieve when all parties have aligned goals.

Ilona Rose House has been recognised as the first building in London to use a minimum of 75% recycled aluminium in its façade.

By using 52 tonnes of CIRCAL 75R recycled aluminium, the scheme produced a saving of 326 tonnes of CO2 emissions compared to if the average primary aluminium had been used - that’s the equivalent of running 71 cars for a year.

Launched in 2018 by the Norwegian group Hydro, the new alloy consists of a minimum of 75% post-consumer scrap.

Aluminium can be used repeatedly without loss of quality and re-melting it for new uses requires only 5% of the energy needed to produce primary aluminium, so the higher recycled content of post-consumer scrap, the lower the carbon footprint. The make-up of CIRCAL 75R - 75% post-consumer scrap, 10% process scrap, 15% primary ingot - guarantees a carbon footprint of 2.3kg CO2 per 1kg compared with the European average for primary aluminium of 8.6kg CO2 per 1kg.