Maximising efficiency and quality in the UK construction industry
Facing a myriad of pressures ranging from poor productivity to spiraling costs, the construction sector has in recent years been urged to embrace more modern methods of construction to deliver at pace new homes, commercial space, amenities and infrastructure.
Among a series of recommendations in his groundbreaking 2016 report, ‘Modernise Or Die: Time To Decide The Industry’s Future,’ sector expert Mark Farmer argued for “increased levels of investment in R&D and innovation in construction by changing commissioning trends from traditional to pre-manufactured approaches.”
Offsite modular construction—making parts for a building or even an entire structure in a factory setting—can certainly speed up delivery and ensure quality outcomes. Yet while it is widespread in other countries, including Japan, such offsite activity is a relatively new concept in the UK.
The rising popularity of offsite construction techniques
Nevertheless, the use of offsite construction elements such as timber frames, brick slips and pre-cast concrete components has grown, and the UK government has estimated that around 7% of total construction output, worth in excess of £1.5 billion, has been created by offsite methods.
Examples include the Larkhill housing development on Salisbury Plain in Wiltshire, which saw timber frames provided by Stewart Milne Timber Systems and Taylor Lane Timber Frame play an important role in speeding up the delivery of hundreds of new homes for military personnel.
And it’s not just homes which are leveraging the advantages of offsite construction. Infrastructure projects are benefitting from factory-made components, too. Take HS2. The controversial rail route between London and Birmingham features dozens of viaducts, bridges and tunnels, many of which have to be constructed and erected on difficult-to-access sites.
It pays to minimise disruption—and is more environmentally responsible—on and around HS2 sites, many of which are in nature-sensitive areas. For a viaduct crossing the Thame Valley, north west of the Buckinghamshire town of Aylesbury, HS2 decided to use factory-made concrete parts.
When it is completed, the 880-metre-long viaduct will feature 72 huge concrete beams, each weighing 90 tonnes, supported by 68 piers weighing 42 tonnes each. Both the beams and the piers are being made by Spanish company Pacadar at its factory on the Isle of Grain in Kent. The components are then transported by lorry to the Thame Valley site, where they are craned into place and bolted together.
It is the first time an offsite construction method has been used to build a viaduct of this size, according to HS2, and as well as cutting the time to delivery it means less construction vehicle traffic through the area. HS2 also claims the factory-made sections mean less embedded carbon; 19,000 tonnes less, to be precise, compared to a previous design.
When weighing the benefits of offsite construction, the carbon issue is important. Offsite manufacturing is increasingly seen as an ideal way to help meet the goals around heading toward net zero and counter the current situation, which sees the built environment as a major contributor of carbon emissions.
Eco-building firm TG Escapes argues offsite fabrication results in major carbon savings when compared to traditional onsite processes.
“By manufacturing modules or panels in a controlled factory setting, energy use and waste generation are both greatly reduced,” it says. “From there, consolidated deliveries and swift onsite assembly further slash the carbon impact compared to a traditional brick-and-mortar build.”
The company points to studies that show offsite projects can achieve 30% lower emissions from energy use and 60% less from transport.
However, despite the apparent benefits of offsite construction, it can be fraught with issues, not least because the rest of the industry, from clients to suppliers, aren’t quite ready for it.
Can offsite construction solve productivity issues?
While building homes in factories and transporting them to a site, ready to erect, has been seen as a way to tackle the housing shortage, offsite modular construction has yet to prove the panacea to the UK’s housing crisis that many had hoped for.
Earlier this year, Legal & General announced it was closing the doors to one of its factories that it had previously predicted would produce thousands of modular homes.
The finance giant said that, following a consultation process, it planned to close its plant in Selby, North Yorkshire, by the middle of 2025. A slower-than-hoped-for pipeline of business meant the operation was unsustainable, the group said.
Another modular homes specialist, Urban Splash, went into administration last year, pointing the finger at operating issues at its Alfreton factory.
So when it comes to considering the delivery of a project, what should one go for? Onsite delivery or offsite manufacture?
While offsite construction offers a degree of certainty and quality assurance, such activity can come at a higher cost than traditional methods. According to engineering and design specialist Bryden Wood, these “can include transportation (a prefabricated room is mostly air, after all) and heavy plant for lifting modules into place.
“Unless modules are fabricated on a just-in-time basis they also have to be stored, which costs money, especially if that storage needs to be sheltered from the elements. 3D modules also occupy large amounts of factory floor space and therefore absorb a high proportion of factory overheads.”
Bryden Wood says it wants factories that produce components for the construction industry “to be more like the best factories making consumer goods: highly efficient, controlled and focused on achieving the highest throughput for the lowest cost, without compromising on quality.”
Should you choose offsite construction for your project?
When considering whether to deliver a project using offsite methods, US modular construction firm Modern Building Systems spells out the points to bear in mind.
First, establish whether off-site construction is the best job cost option; sometimes it might not be. Then identify repeatable elements and consider your delivery schedule. Site complexities and location need to be considered, as does a workable procurement strategy. And is the labour force equipped to do the job?
Clearly, offsite manufacturing has enormous potential, and a number of companies find themselves at the vanguard of what is still a nascent technology.
With many looking for the UK to use as many options as it can deliver the built environment, particularly the homes, that we urgently need, the rush to develop more offsite expertise can only increase.