The UK’s prefabrication industry is flourishing, with offsite methods of construction being incorporated into a myriad of developments to deliver time and cost savings as well as significant sustainability improvements.

Here, Martin Goss, Managing Director of Mtech Consult, a leading UK independent consultancy in Offsite Construction methods, discusses what the rest of the world learn about this low-impact building technique to start reaping the ecological and economic benefits.

In the UK, the benefits of offsite construction (OSC) are widely acknowledged: the shorter build times ensure less time is spent on site and a more immediate return on investment, and the reduced work required on site lessens health and safety issues and limits delay through the UK’s inclement and changeable weather. In addition, increasing engineering within a controlled environment ensures the highest levels of accuracy and, therefore, fewer costly snagging issues. Perhaps more significant for an increasingly environmentally conscious industry are the substantial sustainability improvements that offsite construction methods can achieve, both during manufacturing processes and the building’s in-use performance.

Going global – impact measurement

Mtech Consult has worked in a global capacity in both the public and private sectors, experiencing how different countries view, manufacture and implement fast-track offsite construction methods.

In every case, it’s been clear that a method for properly determining the environmental performance of offsite construction compared to that of traditional building methods has been essential. The most credible way to measure the environmental improvements of a building method or product is to conduct a cradle (extraction) to grave (re-use and/or recycling) Life Cycle Assessment based on the Building Research Establishment (BRE) methodology.

For example, measuring the environmental impact of volumetric modular construction for housing in this way and comparing it to traditional back-to-back building methods, shows that OSC can typically lower the overall footprint of a project by an impressive 38%. It can also deliver a 42% reduction in CO₂ and yield a 21% improvement in the use of energy for building and maintenance.

The way a nation builds is a result of its social, political and economic history, and countries that have traditionally been heavily unionised can find it difficult to introduce new construction methods if a Union does not support them. However well-intentioned the motivation for not backing emerging techniques - whether job preservation or economic vigilance in a time of global recession - this could stifle innovation, which is the lifeblood of sustainability.

And, although craft-based construction can be a financially and socially sustainable way to build, government figures show that it is certainly not the most environmentally sustainable. Using a typical offsite volumetric module-based apartment build as an example, there were 90% fewer vehicle deliveries to site than when using traditional, non-prefabricated building methods.

Waste reduction is another significant sustainability advantage feature of deploying offsite construction techniques. Research conducted with the government’s waste reduction department, WRAP, shows that factory-based construction methods can reduce material waste by up to 90%.

Spreading sustainability through offsite

So, how to further convince the built environment sectors in the UK to adopt offsite construction methods? In the public, private and commercial arenas, repeatability and predictability are of huge importance, as is time certainty and, of course, sustainability. Offsite construction certainly delivers on each of these requirements, and if adopted early in the design process can significantly reduce build times depending on the project.

When it comes to domestic dwellings, typically up to three weeks of an 18 week build schedule can be shaved off using offsite methods. And, when faced with a worsening housing shortage in an area such as social housing, any time saving is a positive one.

What next for OSC?

To some extent, the procurement process needs to change its model to fully accommodate offsite construction. Manufacturers of these systems really need to be consulted at the design stage, because the earlier in the process offsite construction methods are specified, the greater the time and cost savings, and the more influential and effective the environmental benefits.

The future for OSC in the UK is certainly looking bright. Innovations such as bathroom pods or volumetric modular bedrooms complete with curtains, soft furnishings, wallpaper, tiles and taps for use in hotels, student accommodation and the like – give the option of reducing or adding to a building with complete repeatability in line with demographic demand and are becoming increasingly popular. What’s more, the factory environment is best placed for furthering other developments, such as the use of post-industrial and post-consumer recycled materials, and methods for building more while using less.

The advances within the UK’s offsite sector have already positioned it as the worldwide ‘centre of excellence,’ with many countries across the globe watching its progress in trialling new systems. With new entrants to drive towards innovation gathering speed, now is the ideal time for the rest of the world to capitalise on the advances being made in the offsite sector. The offsite sector presents a great opportunity for setting the construction agenda while occupying an influential thought leadership position on both a national and international stage.

CASE STUDY

Lessons worth learning - sustainable schools

Under the UK Government’s Building Schools for the Future (BSF) programme, two new low-carbon schools in Sunderland needed to be completed sustainably and on time, ready for the start of the new school year. The schools required plant rooms, or energy centres, with low carbon footprints that could integrate zero carbon onsite generation with traditional high-efficiency components such as condensing boilers and variable speed drive pump systems.

Heating, ventilation and air conditioning specialist, Armstrong Integrated Systems, which worked with Mtech Consult on the Innovate Offsite feature at Ecobuild in London this year, was engaged to cut the overall project timescales, streamline the installation of building services and keep traffic on the site to a minimum. Each of the fully integrated LZC prefabricated energy centres was constructed at Armstrong’s UK manufacturing facility, before being delivered to site fully-assembled.

Manufacturing the plant rooms’ offsite made it possible for construction to proceed concurrently with the rest of the project, and meant that assembly could continue regardless of the weather, all ensuring work finished on time and the schools could open in line with the start of the new academic year.