Factory Thinking has well and truly arrived for construction in the UK. Whatever you call it – jumping factories, flying factories, offsite factories or modular building – construction is increasingly resembling manufacturing.
The benefits are becoming too strong to ignore: higher efficiencies and certainty around build programme, cost, quality control and health and safety.
But the very word “prefab” will still have some not so fab connotations in some minds. This post-Second World War legacy saw cheap and temporary builds as a useful, if short-sighted, solution to surging needs in housing and infrastructure. In the intervening decades, despite a few successes, the industry has become fragmented and yet to reach critical mass.
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But in recent years there has been a change. Calls by successive governments to boost housing and infrastructure, and do it cheaper, almost forced the industry to look again at prefab. In the decade after the financial crisis, offsite surged and now accounts for more than 7% of total construction output, worth more than £1.5bn to the UK economy.
According to one industry survey 57% of 22,544 homes planned by 17 of the UK’s largest housing associations will be constructed using offsite methods, including timber frame and modular construction.
And in national infrastructure, the i3P group of 22 major clients and suppliers have stated that manufacturing is one of three “strategic themes” in the recently released Technology Roadmap for the industry.
But, there’s still a way to go before the UK embraces offsite the way that Germany, Japan or other countries have done, says Ramboll managing director Matthew Riley: “I step back and look at Denmark, that’s a country that’s been doing it [prefab] since the 1960s, and 90% of construction there is off site. To the extent that you’re a specialist if you do insitu. Which is the complete reverse of what we do in the UK.
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“This was because Denmark had a major labour crisis in the 1960s, which forced the industry to change the way it delivered. And they’ve not gone back since. And you might argue what’s the equivalent crisis… Have we got one? Is it Brexit?”
While there’s no labour crisis in the UK, yet, Brexit tremors are starting to result in lower growth for the industry as clients become more reluctant to spend and question long-term commitments. The Office for National Statistics estimates that the construction sector contracted by 0.9% in the second quarter of 2017.
And while offsite might make sense amid macro changes on Brexit, it also makes common sense at the street level. As concerns over air quality and traffic disruptions rise, moving messy, noisy and obstructive construction away to a controlled environment makes practical sense, especially in big cities. This could become one of the most convincing arguments for Factory Thinking as the population increasingly gravitates towards cities.
Denmark had a major labour crisis in the 1960s which forced the industry to change the way it delivered
Matthew Riley, Ramboll
Perhaps the best use of prefab recently has been London’s Crossrail, certainly in terms of quantity. A total of 250,000 concrete tunnel segments were manufactured near to site at the specially fitted out Old Oak Common factory. In another factory, huge robotic 3D printers created large concrete moulds from wax used to cast concrete panels. And that’s not mentioning the tunnel boring machine, in a way its own flying factory, supplied by other factories.
Other examples include London’s iconic Leadenhall Building which, with its tight footprint and constraints around site storage, was amazingly 85% manufactured offsite. And Heathrow’s Terminal T2A, with its deployment of modular M&E, claims to have saved 1M onsite working hours.
The most prominent name in Factory Thinking is Laing O’Rourke, namely after making some of the largest investments in offsite manufacturing facilities, such as its Explore Industrial Park in Steetley. It also leads a 21 company consortium on another facility that aims to deliver homes 50% faster. But it is far from the only player.
What if the offsite factory mentality was moved on site? That’s what’s happened at the “jumping factory”, recently trialled on a 30-storey residential building in east London by Mace. The 10-storey “factory” is a steel frame and tent that houses the gantries and cranes that configure modular elements. The jumping factory is attached to the building’s exterior and jacked up as floors progress. While speeds of one storey a week are claimed, there have been issues around logistics and deliveries to site.
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Another prototype of Factory Thinking is the flying factory. Skanska is pushing this wagon, where the manufacturing takes place in a pop-up facility, which is rented, built or occupied, near to site for the duration of the programme. These factories are promptly abandoned at project’s end, and “fly” elsewhere.
The flying model avoids some of the burdens of the larger offsite manufacturing facilities, such as higher transport costs and the large amount of initial capital investment. A pilot project in Slough, which will fabricate fully serviced “utility cupboards” for flats at London’s Battersea Power Station, has been supported by a £750,000 grant from Innovate UK.
Developers are getting in on the action too. Vision Modular Systems, associate company of developer/contractor Tide Construction, is putting up large residential towers in a matter of months. The company makes the fully fitted out concrete-based steel-framed modules offsite, fits them together, then transports entire apartments by lorry to site where they are craned into place at the rate of 15 a week.
Could even further gains be made once automation replaces labour? Vision managing director Kieran White says the next step will not be robots but “supply chain development”.
The capability is quite transformational and it puts developers and clients a lot more in control of the process
Matthew Riley, Ramboll
“People will often quote you the trend that the major car manufacturers follow – build a plant in a certain location, then within a period of time all the key suppliers will be dotted about it as a means of servicing it reliably,” he says.
“This [model] applies to [Vision’s] modular in particular because we have a broader supply base than, say, a precast concrete panel maker who has a limited supply chain base of rebar, aggregate and cement. We need everything from electrical fittings, kitchen fittings, doors, windows – all delivered at the right amount and at the right time to ensure we are still making those efficiency gains.”
White adds that offsite construction has better environmental and low carbon credentials than traditional ways of working.
“Where we go further on this is in transport – the number of transport movements for a project is vastly reduced. Likewise your waste in delivering materials to a production line, as opposed to on site, hauling them up hoists, large sideways movements, you will get more damage and wastage. I think the industry as a whole needs better data around this, but it is definitely improved over traditional methods.”
Are we too limited by our imagination? It’s about thinking differently, changing the model
Matthew Riley, Ramboll
And as technology makes traditional methods faster, “rapid option appraisal” is enabling landowners and developers to model and manipulate designs, optimised at later and later stages, says Ramboll’s Riley. “The capability is quite transformational and I think it puts clients and developers a lot more in control of the process. Allows for significant time compression as well. I think the benefits are huge going forward, and through all of that you get predictability.”
Riley adds that one of the challenges to innovation is procurement. “Where is the incentive to invest in different design, different business models, going forward? You can deliver significant amounts of value to those projects and programmes by driving a far more efficient solution. That’s the sort of paradigm shift we need to make.
“But then are we too limited by our imagination? It’s about thinking differently, changing the model. Some of that might require policy, whether that’s through central or local government.
“I think the next generation of engineers will have a fundamentally different skillset. I could see a world in, say, five years where 30% to 40% of our resource is non-engineers. Those sorts of changes we’ve already started to see come through already.”
Close to full automation
Certainly this is reflected elsewhere in the company, where the design and modelling for gantry systems is coming close to full automation. With a background in product design, Ramboll director of bridges Simon Benfield is leading the system and says part of Factory Thinking is simply about reducing potential changes and uncertainty. “If you’re repeating tasks, you gain confidence in the process, you can do it better, faster, and they feed back to us, what the little niggles in the process are, and we’ll try to tweak designs to take those out.
“Because everything is linked, as change occurs through the project, and naturally it always does … these systems reduce the time and money spent on addressing change.
“And because you can leave the design stage later and later, towards the end of the project, it reduces the chance of change even happening.”
But there is increasing competition from other civil engineering and software companies hoping to build similar systems. The Ramboll team seems confident they are out in front. “We come across other companies doing this, from time to time. But I don’t think there’s anyone who’s taken it quite to this level yet,” says Benfield.
What’s clear from talking with those working in offsite construction – those with the specialised, technological roles – is a general view that Factory Thinking has a far bigger role to play in the industry, than it currently does.