Offsite construction

Major UK contractors have been adopting offsite construction over the past decade due to cost, health and safety, and environmental factors. So, what exactly is offsite construction and how can offsite construction help deliver projects on time?

Principal contractors such as Mace, Laing O’ Rourke, and Balfour Beatty are investing in offsite manufacturing for landmark projects. When considering the many benefits this might make you question why Offsite construction is not more widespread.

What is offsite construction?

“Offsite construction is simply the method of manufacturing and part assembling components away from the live project site” (Design Buildings, 2020). It is often referred to as ‘Prefabrication’ or ‘Modern Methods of Construction’ (MMC) and DfMA. Typically, within offsite construction facilities you will have a highly skilled team of welders and fabricators that will manufacture prefabricated solutions from comprehensive design drawings.

What are the key benefits of offsite construction?

Reduced risk of Health and Safety issues
When pre-fabricated solutions offsite this takes the human resource input away from the site environment and therefore reduces the health and safety risk. As the onsite perspective of the construction industry becomes more regulated, certain working practices are inhibited, for example hot works permits etc. Offsite construction answers this challenge as it takes the risk away from the site environment.

Cost efficiencies
Moving site processes into an efficient workshop environment invariably reduces cost. One of the biggest outlays within a M&E installation is labour. With Offsite construction labour can be kept to a minimum as the prefabricated solutions have been fully or part assembled before they arrive on-site.

Delivering M&E installations on time
When implemented correctly, offsite construction combined with MMC can help M&E contractors complete installations on time. For example, if a factory has produced prefabricated solutions that are fully or part-assembled before they arrive on-site, then they can be quickly installed on-site, thus reducing build times. When comparing offsite construction to traditional building techniques, offsite tends not be heavily influenced by the traditional onsite sign-off hierarchy, as quality management processes are handled offsite to reduce the risk of defects when arriving on-site.

Quality Control
In a controlled factory environment with total quality management procedures in place, errors are reduced, eliminating the traditional challenge where supports built onsite may have to be re-worked due to limited quality control practices.

Positive reduction in project carbon footprint
The Net Zero 2050 carbon emissions target came into force in 2019. This immediately put an emphasises on the construction and M&E sector to put into practice environmental and sustainable carbon initiatives. According to the global report the construction industry contributes to 39% of all carbon emissions. Examples of how offsite construction can help meet the Net-Zero 2050 carbon emissions target are:

  • Product waste: eliminates excess offcuts such as channel and studding thus reducing waste.
  • Where traditional onsite methods would usually include hot works, offsite facilities have a tendency to utilise sustainable modular solutions as they are a carbon friendly alternative.
  • As offsite is often delivered in part or full assemblies this greatly the amount of packaging waste.

Reduction in space used on-site
As solutions are prefabricated offsite there is no need to have cutting and assembly areas on-site. Another key area is the reduced amount of labour and tools onsite. Each of these factors are hugely beneficial for live project sites such as Hospitals, Schools, Prisons and High-rise residential buildings where space is limited and therefore disruption to other areas of the site are reduced.


It is now down to the M&E industry and contractors to challenge the status quo. There are clear economic, productivity and health and safety factors which put offsite construction as a favourable choice over and against traditional onsite construction. The question is, will project stakeholders accept offsite construction as a viable alternative?


  1. Global Status Report, 2017, Access: []
  2. Rownload, M (2020); ‘Offsite: how firms are overcoming the barriers’ Access: []