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Fragile Roofs: The Invisible Killer
A worker steps onto what appears to be a solid roof panel. There is no warning — no creak, no flex, no visible sign of weakness. The surface gives way. The fall is measured in metres; the injuries, in some cases, in the rest of a lifetime.
Falls through fragile roofing materials are the single most common cause of roofing deaths in the UK construction industry — more frequent even than falls from roof edges. The HSE's Health and Safety in Roof Work guidance (HSG33) confirms this as the headline finding from decades of fatal accident data: fragile surfaces kill more roofers and construction workers than any other single roofing hazard.
For the broader context see our Roof Work Accident Statistics UK and Falls from Height Statistics UK: The Definitive Guide.
Key Facts & Figures (Overview)
- Falls through fragile roofing materials — rooflights and asbestos cement sheeting — are the single largest cause of roofing fatalities in the UK construction industry (HSE HSG33)
- Roof work accounts for a quarter of all deaths in the construction industry
- Falls from height killed 35 workers in 2024/25 — the leading cause of workplace death for over two decades
- Roofers are estimated to be five times more likely to suffer a fatal accident than workers in other sectors
- All roofs should be treated as fragile until a competent person has confirmed they are not — HSE guidance
- Asbestos cement (AC) sheets, widely installed in agricultural and industrial buildings before the 1980s, are among the most dangerous fragile roofing materials — they deteriorate over time, losing structural integrity while maintaining their appearance
- Rooflights are particularly hazardous because they can be difficult to identify in certain light conditions or may be obscured by paint or weathering
- The majority of fragile roof fatalities involve workers who were not aware that the surface they were working on was fragile
- Non-roofers accessing rooftops for maintenance, cleaning, or survey work are frequently involved in fragile roof incidents — they may lack the roofing-specific training to identify and manage fragile surface risks
- Construction accounted for 35 worker fatalities in 2024/25 — with falls from height the dominant cause at over half of deaths across the five-year period
What Makes a Roof Fragile?
A fragile surface is one that cannot safely support the weight of a person, their tools, and any materials they may be carrying. Fragility in roofing materials is not always obvious, and experienced workers have been killed by surfaces they believed to be safe. The key categories are:
Asbestos cement (AC) sheets: Used extensively on agricultural buildings, older industrial units, and commercial premises constructed before the early 1980s. AC sheets deteriorate with age — the cement matrix breaks down, asbestos fibres become exposed, and the structural integrity progressively fails. A sheet that supported workers safely when installed 40 years ago may now shatter under a person's weight. This is the category most frequently associated with fatal falls through fragile roofs.
Fibre cement sheets: The non-asbestos replacement for AC roofing carries similar fragility risks as it ages and weathers. All sheeted roofs — regardless of material — should be treated as fragile unless confirmed otherwise.
Glass rooflights: Traditional glass rooflights, particularly those in older buildings, can fail under load. Wired glass, common in industrial buildings, provides little additional structural support.
Plastic rooflights: GRP (glass-reinforced plastic) and polycarbonate rooflights are extensively used in industrial and commercial buildings. New GRP rooflights may meet non-fragility standards; older or deteriorated GRP rooflights have often lost their structural integrity entirely while still appearing visually intact.
Older roof coverings: Deteriorated bituminous felt, aging zinc roofing, and other legacy coverings may have become fragile with age.
Why Workers Fall Through Fragile Roofs
The pattern in fatal fragile roof incidents is consistent:
Failure to identify the hazard: The worker, maintenance team, or contractor was not aware that the roof material was fragile — either because no pre-work survey was conducted or because the information was not communicated to the person working on the roof.
Relying on appearance: Fragile surfaces often look identical to non-fragile surfaces, particularly in dull light or when viewed from a distance. Workers cannot assess fragility by sight alone.
Stepping on a rooflight: The rooflight was not visible (obscured by paint, overgrowth, or standing water), was not clearly marked as fragile, or was assumed to be structural because it appeared solid.
Removal of covers: Protective covers over rooflights were removed for access and not replaced before the area was re-entered.
Not applying the precautionary principle: The HSE's guidance that all roofs should be treated as fragile until confirmed otherwise was not followed.
The Legal Requirements for Fragile Roof Work
The Work at Height Regulations 2005 and HSE's HSG33 guidance set out clear requirements:
Pre-work survey: All roof work must begin with an assessment by a competent person of the fragility of all surfaces that workers may walk on, rest equipment on, or fall against. This survey should document all fragile areas and specify the protective measures required.
Risk assessment: The risk assessment must specifically identify fragile surface hazards and specify the control measures in place to protect workers.
Control measures for fragile areas: The hierarchy of control for fragile surfaces is:
1. Avoid the need to work on or near fragile surfaces where possible
2. Use load-spreading equipment — crawling boards, staging boards — to distribute weight over a greater area
3. Use barriers, covers, or nets to prevent falls through identified fragile areas
4. Ensure fragile areas are clearly marked and that all workers are informed of their location before work begins
Training: Workers must be trained to identify fragile surfaces, to implement and use load-spreading equipment correctly, and to recognise the warning signs of surface deterioration.
Rooflights: The Specific Rooflight Protocol
Given the frequency with which rooflights feature in fragile roof fatalities, the HSE provides specific guidance:
- All rooflights must be identified before work begins — including those that may be obscured or disguised
- Purpose-designed rooflight covers — secured in place and clearly labelled with hazard warnings — must be fitted over all rooflights in working areas
- Covers must not be removed unless specific arrangements have been made to protect the opening
- Where rooflights cannot be covered, barriers must be erected around them at a safe distance
The standard warning marking for fragile rooflights is a yellow or orange warning notice attached to or adjacent to the rooflight, clearly visible from the direction of approach.
Written by Working at Height Experts
This guide was produced by the team at Working at Heights Course, a UK provider of RoSPA and CPD-accredited online working at height training. Our courses specifically cover fragile roof identification, rooflight hazards, and the correct application of load-spreading and protective measures. For related data see our Roof Work Accident Statistics UK, Falls from Height Statistics UK: The Definitive Guide, Construction Falls from Height Statistics UK, and Roofing Accident Statistics UK.
Sources & References
- HSE – Health and Safety in Roof Work (HSG33) – https://www.hse.gov.uk/pubns/books/hsg33.htm
- HSE – Fragile Roofs – https://www.hse.gov.uk/construction/safetytopics/roofwork.htm
- HSE – Work-Related Fatal Injuries in Great Britain 2024/25 – https://press.hse.gov.uk/2025/07/02/latest-annual-work-related-fatalities-published/
- Filon – What 2024/25 Data Tells Us About Fatal Workplace Falls – https://www.filon.co.uk/fatal-falls-from-height-data-and-workplace-safety/
