The Many Flavours of Offsite Construction – A Concise Guide

While the advantages of offsite construction methods are becoming better understood, their use in the UK continues to lag behind other parts of the world. Offsite still accounts for only a small percentage of UK construction output.

One reason for this may be that the term ‘offsite’ covers a range of very different technologies and methods. Maybe when somebody thinks that offsite isn’t appropriate for a particular project, they’re not thinking about the right kind of offsite. There might also be a hangover from the negative press (largely unwarranted) that timber framed construction received in the past and that people associate with offsite.

Possibly there’s also a misunderstanding about the full scope of what offsite construction means. People may focus on the methods and materials rather than the substantial project advantages. It isn’t just about assembling or installing prefabricated components or structures onsite. There’s a whole process of design, engineering and planning that goes into delivering the substantial timing, labour, performance, quality and productivity benefits.

As with all things, offsite ranges from the simple to the complex.

At a basic level, manufacturing major structural units such as ring beams in a factory and shipping them to be installed onsite is a form of offsite construction.  These approaches are becoming increasingly common. Greater precision and the reduced need for skilled labour are the main drivers.

Another simple form of offsite construction involves pre-assembled components such as doors and windows that can be installed rapidly onsite using semi-skilled labour. While there are some time savings, the advantages are nothing like as extensive as with a more comprehensive offsite approach.

There is also modular or volumetric pre-assembly. This could mean shipping fully fitted-out modules such as bathrooms or plant rooms to be installed into a building framework. It can also mean providing the structure as completed modules that are fitted together onsite. The characteristic of this method is that structure encloses usable space. Applications of volumetric pre-assembly can be limited where site access is difficult.

Finally, there are panelised systems that is probably the most flexible and functional combination of all offsite. These are used as infill for steel, concrete or timber frames or to form the load bearing structure of the building. These techniques are also commonly combined with volumetric construction using pre-assembled bathroom pods, for example to maximise productivity.

Panelised systems offer excellent design flexibility and include metal frame, cross laminated timber (CLT) and Structural Insulated Panels (SIPs) such as the Innovaré System. As the name suggests, panels are manufactured to precise dimensions in an offsite factory environment. They are shipped to the site in a controlled sequence for assembly into the final structure.

Because panelised systems suit a wide range of designs and external cladding, a finished building is visually indistinguishable from one made using traditional methods. Except, of course, that it will be finished much sooner.

One big advantage of SIPs is that they combine load bearing capabilities and excellent insulation within a single panel; onsite operations are reduced to an absolute minimum compared, for example, to metal frame systems.

Thermal and acoustic performance is also easier to guarantee as performance is designed into the panels, and thermal bridging losses and air permeability are minimal. The engineering-led process also resolves technical issues early in the design phase, eliminating the risk of late redesigns and onsite reworks.

So to find out more about how the System could be the right offsite solution for you, get in touch with Innovaré today on 0845 674 0020 or visit our website.