Dr. James Glockling explains how insurance works and outlines some of the challenges of insuring a natural building.
Interview with Dr. James Glockling
Dr. James Glockling began his career with the Loss Prevention Council, the insurers’ hub for studying fire, security, flood and other loss‑mitigation challenges. He later deepened his expertise at the Building Research Establishment (BRE), and then worked at the Fire Protection Association before setting out on his own as a consultant. His clients are wide-ranging, including insurers and even the military, helping them build resilience and mitigate risks in high‑risk scenarios—from multi-storey apartment blocks to the confines of a submarine. His work reminds us that, regardless of setting, safety rests on the same timeless principle: robust materials and well‑designed systems protect the people who depend on them.
In this podcast interview we discuss everything from one-off homes to high-rise, multi-dwelling projects.
Insurance protects the individual against disaster
Insurance began as a collective safety net, allowing many people to share the cost of rare but catastrophic events. By pooling premiums, an insurer can compensate an individual when a loss occurs, turning an unpredictable disaster into a manageable financial outcome. This principle still underpins modern home and commercial policies, even as building practices evolve. Understanding insurance as a partnership rather than a pure expense helps homeowners see it as part of responsible building.
“Insurance was originally set up as a means of protecting people against disaster, where you levy a premium on a large group of people to protect the interests of the individual.”
Insurers have to weigh up a variety of risks
Underwriters assess far more than fire. They examine the building’s use, size, occupancy, and any ancillary systems such as solar panels, battery storage, EV chargers, green roofs, or underground car parks. Factors like these may have an impact, so insurers request detailed information on design, materials and mitigation measures. The broader the picture they have, the more accurately they can price a policy and set conditions.
One-off homes should be easier to insure
As insurers always have to think about a complete loss and rebuild, having a single smaller property is a limited loss scenario. As the scale of a building increases so does the potential loss scenario.
Self-builders often choose to construct with timber
Estimated Maximum Loss (EML) is a key metric for insurers
EML is the insurer’s worst‑case estimate of loss from a single incident, expressed as a proportion of the building’s total value. For a 20‑storey tower, an insurer might assume only four floors could be completely destroyed, translating to a 20 % EML. When new construction methods make fire spread more unpredictable, insurers often raise the EML toward 100 %, which drives premiums skyward or leads to outright refusal. Demonstrating a defensible, lower EML is therefore a key part of the underwriting conversation.
Under‑insuring is a false economy
Many owners underestimate the true rebuild cost of their property, declaring a lower value to obtain cheaper premiums. If a total loss occurs, the payout will only cover the declared amount, leaving owners with a significant funding gap. Accurate valuation, combined with robust risk mitigation, ensures that the insurance policy truly protects the investment.
Insurance companies may have their own specialist areas
James says that he used to live in a thatched home and that his monthly insurance premium was what most people would pay for a year. This is because if a thatched roof catches fire then the house will be a complete loss. However, NFU Mutual have made this their specialism and are seen as the go-to provider. This is because they understand the risks, know what conditions matter and have a history in this area.
Water damage is the most common insurance claim
Water loss accounts for billions of pounds of damage each year and occurs far more frequently than fire. Burst pipes, roof leaks and flood ingress can rapidly degrade timber, leading to rot, mould and structural failure. Early detection systems—wireless tape sensors, automatic shut‑offs—are increasingly expected by insurers, especially for mass timber projects where hidden water would otherwise go unnoticed for months. Proactive monitoring can therefore reduce both risk and premium.
When it comes to timber, voids present a fire risk
As timber is combustible, the design of a building becomes crucial. Voids can allow smoke, heat, and flames to spread rapidly, bypassing sprinklers and complicating firefighter access. Mass‑timber panels (CLT, glulam) reduce voids but may be subject to smouldering, which can persist for many hours and even lead to the flames reigniting. These behaviours force insurers to demand rigorous fire‑stopping, compartmentation, and sometimes hybrid designs to keep the EML manageable.
A self build home that used cross laminated timber
It’s essential that fire‑stopping is correctly installed
Every penetration—pipes, ducts, cables—in walls and floors must be sealed with a fire‑stopping material. Missing or poorly installed fire stops create pathways for flames and smoke, dramatically increasing the EML. In light‑timber frames, the sheer number of voids makes comprehensive fire‑stop inspection essential. Regular audits, preferably by a dedicated Clerk of Works, provide the documentary evidence insurers demand. This may make a boring photo collection but it will be a valuable one.
“I haven’t been to any fire in a building where I haven’t found the fire-stopping either missing or misplaced or just absent.”
Hybrid designs with concrete cores satisfy insurers
In high-rise buildings, combining timber with non‑combustible elements—concrete cores, steel columns or concrete plinths—offers insurers a tangible safety buffer. A concrete core protects against fire spread, provides a stable fire‑fighter access route, and serves as a flood‑resistant base. Such hybrids offer the best of both worlds, with the carbon benefits of timber while delivering the structural and fire‑performance assurances underwriters look for.
Take photos during construction to provide evidence of good workmanship
Even the best design fails without quality construction. Insurers scrutinise records of on‑site inspections, photographs and sign‑offs to confirm that fire‑stops, penetrations and material installations match the approved design. A diligent Clerk of Works creates a paper trail that can be presented during underwriting and later claims, reducing disputes and speeding up payouts.
“Evidence is everything, and if there’s a Clerk of Works properly reporting on the job as it’s put together, then that can only be of great benefit.”
Insurers steer away from complexity
The industry uses six categories to describe the percentage of combustible material in a building. For example, Structural‑Insulated Panels (SIPs) are often highly combustible, pushing a project into the highest risk tier. When a building lands in the 100 % combustible category, insurers typically raise premiums sharply or decline coverage. Understanding these categories lets designers choose lower‑risk assemblies or offset risk with non‑combustible cores.
The Mass Timber Insurance Playbook is useful resource
The Mass Timber Insurance Playbook, co‑authored by Dr. Glockling and broker Philip Callow, lists 26 features that insurers evaluate in timber projects and offers practical mitigation strategies. It is freely downloadable from the Alliance for Sustainable Building Products website and provides a clear roadmap for architects, engineers and developers.
Increasingly AI is being used in the underwriting process
Insurers are increasingly using artificial intelligence to analyse loss data, identify patterns and refine risk models. By feeding detailed, high‑quality information from the construction phase into these systems, builders can help shape more favourable underwriting outcomes in the future.
Find out more
Mass Timber Insurance Playbook – free download from the Alliance for Sustainable Building Products
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