As the government’s legally binding deadline for reaching Net Zero creeps closer, environmental impacts are starting to shape how the construction industry operates.
It is well known that concrete is a polluting material and that transitioning to timber could bring with it a host of benefits. Yet insurance-related challenges still pose a problem. This post will consider how two of these – fire and water – might be overcome.
Timber on the rise
In May 2022, the Environmental Audit Committee (EAC) stated that it ‘recognises the potential of timber as a low-carbon construction material.’ And the government is also promoting the use of timber through its £1.5m Timber in Construction Innovation Fund, launched in February 2022.
As a result, demand for timber-frame homes is expected to soar. The market is estimated to increase by £70m this year, according to MTW Research, and by more than £150m by 2026.
This shift could be a real environmental boon. Given that the UK’s built environment is responsible for around a quarter of the UK’s greenhouse gas emissions, improvements in this sector could become increasingly important as 2050 gets nearer.
Increased awareness has pushed the efficiency of existing buildings into the spotlight. However, it is embodied carbon – emissions associated with the production of materials and the construction process – that has the greater impact.
Indeed, for an average UK office, warehouse or residential building, embodied emissions represent around 70% of the lifecycle building emissions, according to the Royal Institute of British Architects. Swapping concrete for timber could reduce embodied emissions by around 60% at the individual building level, the Committee on Climate Change estimates.
For all the positivity around timber, however, there remain some serious challenges. Foremost among these is the insurance impact of load-bearing timber products.
Insurers have long been nervous about timber-frame developments because of the perceived increase in fire and water damage risks. As a result, insuring timber buildings has always been more complicated – and higher cost.
1. Fire Safety
Fire resilience poses a threat during the construction and ongoing use of a property. Insurers must ensure that the likely scale of loss in the event of a fire would be less than 100%, which is not necessarily guaranteed by compliance with regulations.
2. Water Exposure
Likewise, the threat of water ingress needs special attention in timber construction. The escape of water represents the greatest category of loss in the domestic and residential sector – and timber is especially susceptible to water damage. There is a risk of engineered timber products decontaminating, leading to structural deterioration from hidden water seepage.
Solutions and next steps
A RISCAuthority white paper published in January 2022 provides “a possible way forward” in response to these two challenges.
One solution is the hybridisation of building methods and materials, which can be achieved in multi-storey buildings by alternating timber and concrete floors. Specifically, the first floor of a mass timber building would need to be concrete, with bathrooms and kitchens located in the concrete core.
Likewise, the Structural Timber Association urges builders to consider the risks at every stage of the building process, including the choice of location and materials. For example, using gypsum in timber constructions can help a building resist fire. Combustible voids in cavities need particular attention: lining, sprinkler protecting or filling these is a crucial way to protect against the unseen spread of fires.
As the industry evolves over the coming years, a proactive approach to insuring timber construction will become increasingly important. Innovative thinking and careful planning can guard against fire and water risks, allowing mass timber construction to star in the race to Net Zero.