Modular Construction

Dr Jim Glockling, Technical Director at the FPA discusses whether, given the pace of construction innovation, enough is being done to avoid another cladding-type construction defect crisis, and what prospective buyers might need to do to protect themselves and their investment.

Put yourself momentarily in the shoes of those who unwittingly purchased homes in poorly clad apartments – and who now find themselves financially and geographically locked in – and you quickly understand the gut-wrenching stress of their predicament. At best they must incur additional costs and put any plans of moving on hold; at worst they are displaced with a severely depreciated asset that might have been their primary investment, pension plan, or a steppingstone to a better future.

It is not the first time this has happened either. Many houses built after the Second World War were later found to have concrete cancer which similarly drastically reduced their value and demanded significant investment to put right. They still cause problems today as they are bought and sold without historical construction problems being made clear. Sadly though, it is likely that long after the necessary corrective actions have been made, mistrust will perpetuate, and marketability will still be influenced by a damaged reputation.

For most people, the purchase of a property is the single biggest purchase they will ever make. Unlike other purchases, people take substantial risks to make it, borrowing money they do not have, paying over the odds through interest, and committing to wide-ranging penalties if they do not keep up payments. In any other endeavour, such as buying a car for example, it is not uncommon to do a substantial amount of research to find one the right one and understand what its reviewed strengths and weaknesses are. There are also a staggering number of resources out there to help you make the right choice such as Which, What Car, AutoTrader reviews etc.

How is it then that when buying a home, little or no research is generally made in respect of the construction method, the materials used, and the associated compliance and quality factors, with a view to understanding whether it protects your investment, safety, and sanity sufficiently? It must be assumed that the trust homebuyers place in the ‘system’ is absolute. The system being the rules that govern how buildings may be constructed, the ability of the construction company to deliver against these rules, and the quality checks made to confirm these rules are followed. This raises several immediate issues.

Firstly, Grenfell and other incidences clearly show that the system of design, build and checking is completely broken within the UK and should not be trusted. Secondly, a factor completely misunderstood by many is that the rules only seek to ensure the safety of the people living in the property – that the building is evacuated before it collapses in a fire. There is absolutely nothing in any UK regulation to protect their investment, to stop it burning to the ground, or to ensure the continuous availability of the building as a home or business premise. Any measures required to do that must be sought out and some construction methods will inherently do that better than others. ‘Compliance’ alone has never been so meaningless to resilience – it really is time for everyone to know their needs, and know their building.

Looking to the past informs to a degree, but building methods are changing rapidly and I would argue that, like it or not, there is a need for everyone thinking of buying a home or business to gen up on the pros and cons of the systems being used. Inevitably, in pursuit of sustainability and cost cutting, modern methods of construction are becoming more combustible, with greater use of wood and petroleum-based insulation materials (ironically both fuels). It does not have to be like that. Non-combustible green alternatives exist but are unlikely to become prevalent until market forces steer things otherwise. Such is the pace of change that prospective owners could be at risk of trailblazing occupation of entirely new building methods – not necessarily a bad thing, but not something that should happen unwittingly.

What does the future hold and is there a risk of another cladding-type crisis? I would argue yes, all too readily. A newer form of putting buildings together is modular construction. Whole apartments, or rooms are built off-site in a factory and stacked at the site to form a building. The benefits are obvious: improved quality associated with factory manufacture rather than site build, speed of construction, and most probably cost. These modules may be constructed of anything from concrete, steel shipping containers, light gauge steel, light timber, and all hybrid possibilities. So, what is the problem? Simply put, inherent in the construction method is that all modules will be surrounded by voids. If the module material is non-combustible then the influence these voids might exert in a fire situation will be less relevant.

However, if the modules are made of timber, or SIPs panels (timber and insulating foam insulation sandwich) as they commonly are, the fastidiousness with which cavity barriers are fitted at every junction (x12 for every module and additional ones around every penetration between modules, such as doors) becomes critical. Note that such a building method also often uses rainscreen cladding meaning that if the cavity barriers are imperfect or not installed, the entire building could be a permeable lattice of combustible voids capable of spreading internal fires out to the exterior envelop where it may spread, and vice versa.

Fires in combustible voids pose one of the greatest risks to whole building loss. Hidden from view, they may develop in their own time, their geometry will accelerate rate of spread, and fire service effectiveness in this situation is greatly impaired. Is this scare mongering? Look at the reports of the majority of recent fires in light timber-framed buildings and the story repeats time and again: “….cavity barriers were omitted or poorly fitted”. Why should there be any greater level of trust for modular construction? Cladding-deficient buildings are, at huge expense, being rectified. Could missing cavity barriers and fire stopping even be retrofitted to a large modular building? Not without almost destroying it.

To insure or lend against any building, there will be a need to demonstrate that it has been put together appropriately. Imagine a situation where several modular buildings perform poorly in the future for the reason of poor fire stopping – perhaps it is associated with a loss of life that would not have happened without this deficiency. Overnight an entire breed of the UK building stock will come under scrutiny – are they safe to occupy? Are they OK to insure? Are they OK to lend against? How do I know if my building was put together properly or not? And so the devastation for homeowners repeats.

The solution lies in Regulation 38 of the English 2021 Building Regulations – a legal requirement to evidence and record that the fire safety credentials of the building meet the requirements of the building regulations. For modular buildings, we have recommended the photographing of the fitment of every cavity barrier within the building. What other approach would work if after a series of unfortunate events in other buildings, questions start being asked of the one you live in 5 years after it was built? But there is reluctance to do this.

Whilst this may seem far-fetched, history dictates that some buildings will perform badly in fire and the most likely cause will be that the safety systems that are the vehicle for combustible building material use were imperfect. Would the average homebuyer know to ask for evidence that the information supporting Regulation 38 has been provided for their building and is sufficient? No, but they need to, and getting to that point is the difficult part. Another cladding-type debacle is unthinkable, but I see little being done to avoid it happening. Perhaps it is time to revisit the concept of Home Information Packs (HIPs) which were repealed in the Localism Act of 2011.

At the Fire Protection Association we are passionate about improving the quality of the built environment, and our goal is to make it a safer place to live and work. The launch of our Know Your Building campaign supports the conclusions and recommendations of the Hackitt Review, which highlighted a general lack of understanding of fire risks, mitigations and management arrangements by building owners and the construction industry. Find out more about our campaign for change!