At a glance
- Modern methods of construction (MMC) are increasingly common in today’s building designs
- While often offering cheaper, quicker or more sustainable options, new construction methods can also introduce a number of additional risks, both during and after the building phase
- We look at some of the leading MMC and what construction customers should consider when using them
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Modern methods of construction (MMC) can often provide quicker, cheaper and more sustainable ways of constructing buildings. This makes them an attractive solution for today’s designers, and construction professionals are increasingly being introduced to them on projects.
However, MMC can also introduce added risks at the construction stage and require extra precautions throughout a building’s lifetime.
We look at some of the leading modern materials and building methods and highlight the key considerations for customers when working with them.
- Timber frames
Timber is considered more sustainable than brick or concrete, making it an attractive option for designers.
However, engineered material, such as cross-laminated timber (CLT), is now enabling timber to be used much more comprehensively, and on much larger projects. A downside of using timber, however, is that it burns and can be vulnerable during construction and the more that is used corresponds to a heightened risk of fire.
As an example of how susceptible these buildings can be during construction, a University of Nottingham building was destroyed in 2014 whilst around 70% complete.
- Volumetric, modular and panelised
Advances in pre-fabrication are enabling larger and more complex components to be manufactured elsewhere and assembled on-site. Components can range from wall panels – such as structural insulated panels (SIPs) – to whole sections of buildings, complete with plumbing and electrics pre-installed.
While using these techniques can be quicker, cheaper and more accurate, extra care needs to be taken to avoid large losses occurring.
Modules, for example, are often built using timber and other combustibles, and may feature voids between each module once in situ. While each module should have built-in firebreaks, it is important that these are not compromised.
“Fire breaks are only as good as their weakest link,” explains Andy. “So, if any aspect of the module is altered – for example new services installed by drilling into walls – then it is important that those fire breaks are reinstated.”
Not doing so can allow fire, smoke and water to spread quickly throughout a building, leading to disproportionately high losses. This not only applies at the construction stage – losses can come to light many years afterwards.
- Bathroom and kitchen pods
Pods are another modular technique, often used for bathrooms and kitchens. Pods are essentially ready-made rooms, pre-installed with fixtures, fittings and services. Once in situ, they only require basic connections to give a finished result. Pods frequently feature in the construction of hotels, student accommodation and other projects where consistency and cost are prioritised.
However, this perception of ease of use is one reason that pods are a common area of loss. When connecting services, such as plumbing, contractors often choose to do it themselves, and make simple mistakes that a specialist tradesman would not.
“People often think that they can avoid the cost of skilled labour, but you still need somebody who knows what they are doing when connecting them,” says Andy. “For example, forgetting to fit supports underneath waste pipes is a simple, but common, mistake.”
Repairing pre-fabricated, component parts in pods can also be incredibly difficult, or even impossible. Sometimes, the only option is to remove the entire pod and install a new one or replace it with more conventional but bespoke fittings incurring extra costs.
“While they are quicker and cheaper during construction, in terms of longevity and what they cost to repair if there is an accident, some MMC can prove more expensive in the long-run,” says Andy.
- Cladding and roofing
With techniques such as Structural Insulated Panels (SIPs) now commonplace for building the superstructure, cladding is often used to give the desired finish, and to protect these vulnerable components from the elements.
Combustibles – such as timber and polystyrene – often feature in external cladding, and there have been several incidents around the world where fires have quickly spread up the side of buildings as a result. It is therefore important to install firebreaks behind cladding, and limit opportunities for ignition or damage – often achieved by commencing cladding from the first floor upwards.
With more than 200 older or historical buildings across the UK destroyed or damaged by fire in 2018, reducing fire risk is a real challenge. As well as old or faulty wiring, many older buildings have voids and cavities in the walls, floors and ceilings, which can provide a clear runway for flames.
Various pre-fabricated roofing systems are also now available, which can be quickly and easily fixed to make a property watertight. As with cladding, it is important to ensure appropriate fixing methods are used.
- Working with customers to disclose MMC
A wide range of MMC are now being used in building designs. Each can alter the risk profile of any construction project, so requires the right corresponding risk management action to be taken.
The use of MMC is always a factor that can influence an underwriter’s decision, so it is important that their use is always disclosed. Customers should therefore be clear on whether MMC feature on any of their construction projects, and carry out further investigations if they are unsure.
For more information on MMC and their risk and insurance considerations, please speak with your local Zurich contact.