Watch our AT Schüco webinar exploring how current and future generations can unlock the potential of modern methods of construction.
The National Audit Office used the term modern methods of construction (MMC) in a report in 2005. The term DFMA (design for manufacture and assembly) has been around for at least as long. Yet it has largely seemed that there has been far more talk than action. Now, however, as this webinar showed, substantial projects are coming to fruition and a lot more activity is planned.
Harbinder Birdi, infrastructure sector lead partner at Hawkins\Brown, talked about his practice’s work for London’s Crossrail at both Tottenham Court Road and Liverpool Street stations. The practice’s involvement was different, since at Tottenham Court Road it was the lead architect, whereas at Liverpool Street it was responsible for executing an initial design by Wilkinson Eyre Architects.
Speakers from left to right: Simon Bayliss, Adam Jones, Harbinder Birdi, Judith Barker, and Adrian Robinson
For the two buildings at Tottenham Court Road, of very different characters, the architect worked with contractor Laing O’Rourke to manufacture major elements at its plant in the East Midlands. ‘It is key that the client buys into offsite from the beginning,’ Birdi said. ‘Crossrail were fantastic.’
The platform linings at the two stations were identical in design, as they are throughout the project. Laing O’Rourke prefabricated the Liverpool Street platforms, whereas Tottenham Court Road was done by a conventional method, enabling a direct comparison. This showed that the precast method allowed the platforms to be laid three times as fast, and with great savings in manpower.
The platforms at Tottenham Court Road Crossrail station are clad in GFRC panels that follow the curved profiles of the concrete tunnels (ph: Morley von Sternberg)
Even more impressive was the work on the Crossrail tunnels, currently the biggest tunnels in Europe. Specialist Bryden Wood worked with Laing O’Rourke on the GRC cladding, making it in a factory so that it was only 12.5mm thick instead of the 25mm initially envisaged. ‘Crossrail enabled the research and development early doors to be able to make the product more effectively,’ Birdi said. This included making mock-ups that everyone could see so that a standard could be set for the work. Perhaps surprisingly, the actual making in the factory was done by skilled operatives who could judge the thickness of material by eye – a marriage of individual skill with the largely automated process.
Delivered by Hawkins\Brown in collaboration with Wilkinson Eyre, Arup, and Laing O’Rourke, Crossrail Liverpool Street station utilises prefabricated concrete building components, including 200 prefabricated platform components (ph: Morley von Sternberg)
Education is another area that has made large strides. Adam Jones, MMC strategic change manager at the Department for Education, said that to date his department has completed 103 MMC schools projects, with a value of £750m, with a further 110 at various stages of delivery. The organisation has built up its framework of projects from some exploratory work in 2015, and is now moving to secondary schools, having initially concentrated on primary provision.
Installation of modular units at Keeble Gateway Academy in North Yorkshire (ph: Portakabin)
Schools are suited to MMC, Jones said, because they ‘tend to have standardised accommodation and associated datasheets, repeatable spatial elements and adjacencies, highly standardised specifications, digitally enabled workflows, and strong pipelines of future workload, delivered through long-term frameworks, leading to contractor-led standardised design solutions and a culture of innovation and collaboration.
If the superstructure, services, internal finishes and substructure can all be made off site, it may be possible to manufacture as much as 90 per cent of the building’s value, Jones said.
DfE has been working with other bodies on a project called GenZero to develop a standardised zero-carbon DFMA school prototype. The aim, Jones said, was to create an ultra-low embodied carbon platform that could be configured in numerous ways to create virtually any school setting.
Measuring 135-metres tall, Ten Degrees Croydon in south London by HTA Design is believed to be the world’s tallest modular housing scheme (ph: HTA Design)
Architect HTA has also been making progress with MMC over the past decade. Managing partner Simon Bayliss talked about the latest project, the 44-storey Ten Degrees building in Croydon. It contains 546 built-to-let homes and was built up from around 1500 prefabricated modules, arranged around two slipformed cores.
Ten Degrees Croydon was delivered – from first concept sketch to handover – in just 39 months (ph: HTA Design)
Bayliss showed that it was possible to create a sophisticated articulated facade, as well as bespoke facilities at ground floor and rooftop level, with this prefabricated approach. It is, he said, particularly suited to buildings that are designed for letting, as little customisation is offered on individual dwellings.
So successful has this been, that the practice is already on site with an adjacent tower.
The iconic Futuro House designed by Matti Suuronen (ph: Adrian Robinson)
A more sceptical approach came from Adrian Robinson, senior lecturer in construction technology at Oxford Brookes University. He looked at the history of industrialised approaches, from Parkhill in Sheffield through Buckminster Fuller’s geodesic domes and Dymaxion House to Moshe Safdie’s precast design for Habitat 67. Many were designed as prototypes yet proved to be the precedent for very little.
Prefabrication, he said, will probably not cost less in financial terms. In fact, unless building on a large scale, the cost may be higher but offset by earlier completion. In fact, he said, ‘The arguments are usually about other factors. If there is significant standardisation, more than 500 units, allowing mass production, then manufacturing makes sense. If there is minimal access to site, or little space for loading and unloading, then you would make off site. A limited time frame, for example in a hospital location or school holidays, may justify this approach, or if skilled labour is unavailable.’
Funded by SEMLEP and the Connolly Foundation, the Bedford College Connolly Centre for Modern Construction provides offsite construction training for the building industry (ph: The Bedford College Group)
There is obviously a lot to discover and the industry needs to learn and research. It is encouraging therefore that the South East Midlands Local Enterprise Partnership has funded an MMC centre at Bedford College to spread knowledge and benefit the region. Judith Barker, director of programmes and governance at the organisation, explained the rigorous thinking that went in to justifying this new facility which will prepare people for the next phase of MMC.