The risks of modern construction methods

  • The social housing sector is increasingly using modern methods of construction (MMC)
  • Trends are emerging of the problems that can be experienced when using modern building methods
  • We share some of the issues being experienced by our customers and offer best practice tips on how to manage MMC risks

Modern methods of construction (MMC) can offer a range of potential benefits –from cost savings to a reduced environmental impact – helping the social housing sector overcome some of the challenges it currently faces.

However, as MMC become more prevalent, trends are emerging about problems that can be experienced when using them.

We are currently assisting two customers that are experiencing near identical issues at their respective housing developments. Here, we share their stories and offer our insights on how to best manage MMC risk.

Unusual discoveries

The two developments concerned were built using common MMC, such as timber frames, wooden cladding and components manufactured off-site. Both developments are very similar in design, comprising around 100 apartments
Almost a decade after construction, alarm bells began to ring once tenants and staff made a number of observations at the properties. These included cracks appearing in walls, uneven floor surfaces and windows and doors not fitting properly in their frames.

Disruptive investigations

Structural engineers were brought in to conduct intrusive surveys and establish the cause of these issues. This involved cutting into walls, ceilings and floors to look at the buildings’ core.

Initial investigations raised major concerns, prompting wider investigations to be undertaken, such as sending samples of the buildings’ materials away for testing and notifying the respective fire brigades.

Major fire risk

During the investigations, it was also discovered that the buildings were seriously lacking in their ability to resist fire.

  • Large voids existed in the internal structures. These voids allow fire to move quickly and undetected throughout the entire building
  • Movement had created holes in walls and around fire doors, breaching vital firebreaks
  • Large holes had been made in firebreaks to install piping and electrical services, but had not been subsequently filled

“A normal block of flats is designed to withstand a fire in a single apartment,” explains Thomas Pickett, Market Underwriter at Zurich. “However, in light of these discoveries, if a fire occurred we would probably be looking at a total loss to an entire building.”

Quick action required

To address the fire risks uncovered, Zurich Municipal and the respective Fire Brigade required a number of additional measures and improvements to be quickly undertaken by the Registered Providers (RPs), including:

  • Fire stops to be reinstated throughout the properties
  • 24/7 security guards to monitor the premises and watch for signs of fire
  • Requiring tenants to immediately evacuate upon hearing an alarm
  • Additional automatic fire detection to be installed in various areas, and the system re-tested to ensure it can accommodate the extra loads
  • Thorough fire risk assessments to be undertaken – recommended to be audited by an independent specialist

A long road ahead

Both customers are currently making a range of risk improvements, in addition to sourcing quotes for the widespread remedial works needed to make the properties structurally sound and fire resistant.

One development has already been advised that they will need to completely demolish and rebuild two of their four blocks.

“One of our customers is looking at estimates in the region of £750,000 just to undertake repair works,” says Pickett. “That doesn’t include the wide range of uninsured, hidden costs the RP is also likely to incur, from things such as rent rebates, alternative accommodation costs and coordinating with all the apartments over the coming years.”

Best practice tips

Problems such as those mentioned above are increasingly being experienced at properties constructed using modern construction methods.

To help prevent these issues occurring, and to identify them early when they do, we recommend RPs follow the following best practice tips:

  • Consult us from the outset – our expert Risk Engineers can suggest a range of intuitive design features to reduce your properties’ risks at little or no additional expense. Upfront savings using MMC may also be outweighed by their likely future costs; we can recommend solutions that will meet both your short and long-term objectives
  • Contractor selection – many MMC are new or experimental, and not all contractors will have experience in using them. Always carry out thorough due diligence when choosing contractors, even for those you have used before, checking especially for evidence of competence with the building methods of each individual project
  • Project oversight – throughout the project, it is important to periodically check that contractors are following design specifications and working to the required standards. An independent project manager is always recommended, as they will have the technical expertise to monitor the complexities of a modern development
  • On-going monitoring – it is important to spot potential issues early to minimise the costs of repair. Educate staff, building managers and tenants on the wide range of issues to look out for and report


Find out more and access helpful guides and insight with our new Fire Risk Resource.