In 2019 UK government departments will favour bids for construction contracts that offer offsite manufacturing. Gavin White and Andrew Mather of Ramboll offer guidance to civil engineers on how to make projects ‘offsite ready’.
Offsite construction encompasses a huge range of disciplines and systems. From factory made concrete, steel and cross-laminated timber components to facade units complete with windows and balconies and modular plant rooms.
However, understanding the offsite benefits for a particular project can be challenging – and only fully realised through a co-ordinated and detailed approach.
While knowledge of offsite construction has been developing in the industry for many years, it remains a diverse and fragmented market.
Realising the benefits of offsite manufacturing for a particular project requires a project-specific, holistic review based on important lessons learned over the past decade.
Understanding constraints
Offsite construction will only deliver value if its constraints are fully understood and lead the design approach.
These constraints can be of manufacture, handling, transportation, lifting or installation, or project site-specific criteria.
Each part is important and should not be overlooked to avoid expensive bespoke solutions late in the project.
The constraints of offsite construction must also be considered holistically by all engineering disciplines. Acoustics, daylight assessments, sustainability criteria, facade details and more must all be developed closely with the architectural, structural and mechanical, electrical and plumbing (MEP) designs from an early stage.
Furthermore, the technical design must align with the procurement, cash flow, supplier availability and client’s funding mechanism.
Offsite reviews
Understanding constraints and involving all disciplines are the basis of Ramboll’s project-specific ‘offsite reviews’ that we are now offering for free on our website.
These are in-depth holistic reviews to find the right offsite systems for a project and culminates in a score for how ‘offsite ready’ the project is. This provides an immediate and comparable indication of the relative merits of different techniques.
A recent example application is the Victoria Quarter in Ashford, Kent. This residential development by Neighbour consists of seven buildings of six to seven storeys, with the majority of flat layouts standardised.
Taking into account the client’s aims for the site and key drivers, we used digital tools linked to our offsite technical database to undertake rapid option assessment of the building forms for the site, ranging from in situ concrete floors, walls and columns to fully fitted steel-frame modules. A master planning tool then determined the offsite approaches that best aligned with the client’s needs.
Alongside technical analysis, the overall approaches to offsite construction were also assessed, including procurement, Building Information Modelling (BIM) and design collaboration, to highlight opportunities for further value. This was compared with industry peers in the project’s offsite-ready score, with benchmarks and further details on how to maximise value.
Conclusion
Construction is changing, with higher standards expected and improvements in delivery time of 50% demanded by the UK government in its Construction 2025 industrial strategy (HM Government, 2013).
The housing shortage fuels the need for change, while regulation and industry adoption of BIM create opportunities for data-driven construction techniques.
Offsite construction and digital design are well-placed to deliver in this space. Indeed, in last year’s Autumn Budget, chancellor Philip Hammond said government departments will, ‘adopt a presumption in favour of offsite construction by 2019’ (HM Treasury, 2017).
Market-leading developers and new disruptors alike are already targeting the off-site market – the rest of construction industry now needs to keep up.
