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Fire risks associated with modern methods of construction

At a glance

  • Some of the materials used, such as polystyrene, are likely to be more combustible than traditional materials
  • These modern materials can give rise to a total loss in the event of a fire
  • Zurich’s underwriters have a wealth of experience in identifying potential problems caused by modern methods of construction

Using modern methods of construction when updating or erecting buildings can offer commercial landlords and real estate investors a cost-effective and quick solution over traditional materials – but a number of factors, such as fire safety, need to be considered when assessing the risks.

With commercial landlords looking to reduce carbon outputs to meet green targets, such as those outlined in the Energy Act 2011, and developers, too, turning to alternative construction methods to cut costs and build times, these materials and methods are seemingly here to stay – although these techniques could ultimately prove something of a false economy.

The dangers of polystyrene

Adding an exterior wall cladding system to provide insulation and waterproofing to a building can bring with it many benefits.

But the process, using either cladding systems or an External Insulated Finish System, or EIFS, can increase fire risks, especially if the insulation sheets used contain polystyrene.

“Whilst there are different grades and treatments, there is no such thing as an incombustible polystyrene,” said Colin Prince, Deputy Underwriter Manager for Real Estate at Zurich. “And once you’ve covered the outside of a building with polystyrene, it aids external fire spread.

“Instead of polystyrene as an inexpensive alternative, you can pretty much always use the safer – in terms of fire risk – polyurethane or polyisocyanurate in its place. Rockwool, which is probably the best of the insulation materials to use, can also be used in a lot of circumstances despite it not being quite so versatile in view of its weight.”

Insulation panels

Insulation panels are used on a range of buildings in various different applications and are available in different materials. They can be found in or under external walls and roof claddings. They offer high insulation values, are easy to work with and recyclable, but may present an increased fire load, especially when comprised of polystyrene, even those classified as fire retardant.

“There’s a growing trend to install polystyrene insulation to the external fabric of buildings to increase thermal efficiency, but fire can then spread up a building more easily,” said Colin Prince, Deputy Underwriter Manager for Real Estate at Zurich.

Installing combustible insulation near heat sources – such as vent pipes, boilers and cooking extracting systems – can also increase fire risks, so this is best avoided at the design stage.

Timber-framed buildings

Timber frame, another modern method of construction, has become increasingly popular, by offering a manufactured off-site solution – making it highly efficient, minimising labour costs and creating little on-site waste.

However, timber is another building material prone to devastating fires, as witnessed after a series of fires in London over the past decade involving timber-framed buildings, which forced the Health and Safety Executive to issue guidance, particularly at the construction phase.

Modular construction

Modular construction, too, where pods are built off site to quicken the build process before being stacked on site, can hit trouble if a pod-constructed building were to suffer fire damage.

For more information

“Following a serious loss, replacing a pod in situ – particularly when at the bottom of a tower – becomes a complex operation,” said Jonathan Scotcher, Underwriting Manager for Real Estate at Zurich.


Innovative construction methods and materials offer new ways of constructing sustainable and affordable buildings. But the majority of these materials are lightweight in nature and combustible, meaning a greater degree of fire spread and therefore leading to increased claims costs.

“Many materials used in MMC are also susceptible to water damage, so putting a fire out can cause as much damage as a fire itself,” said Colin.

When surveying buildings, it is wise to keep records of where potentially combustible materials are being used, so risk management advice can help to reduce the impact of perils that may cause loss relating to modern construction methods.

At the construction phase, it is advisable for a developer to speak to their broker or insurer when considering modern construction methods, especially with large-scale developments.

There’s a growing trend to install polystyrene insulation to the external fabric of buildings to increase thermal efficiency, but fire can then spread up a building easily

Colin Prince, Deputy Underwriter Manager for Real Estate at Zurich

“There is not a lot wrong with using timber frame for a four unit block of maisonettes, although it’s probably not an appropriate method of construction for a £50 million block of student accommodation simply due to scale and the increased potential for disproportionate losses when built using some modern construction methods,” said Colin.

Finally, it is important to note that complying with building and fire regulations does not necessarily imply a good insurance risk. “These regulations concentrate upon life safety and therefore once safely evacuated, little attention is granted to the degree of damage that is likely to then occur to the building,” added Colin.

Zurich, though, is well versed in the level of risk assessment that needs to be considered with these new materials and its underwriters have a wealth of experience in identifying potential problems.

Image © Getty

For more information, get in touch

Colin Prince | Deputy Underwriting Manager | 0207 648 3956

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