Working on Fragile Roofs — How to Prevent Falls Through Roofs (2026)

What Counts as a Fragile Roof or Surface?

The single most important principle is this: treat every roof and every roof surface as fragile until a competent person has confirmed in writing that it is not. You cannot tell whether a surface is load-bearing by looking at it from below or by tapping it. Many materials that have held weight for years become fragile through age, corrosion and weathering — and a sheet that was sound a decade ago may now collapse under a single footstep.

Common fragile materials you will encounter on UK roofs include:

• Asbestos cement sheets — extremely common on older industrial, agricultural and commercial buildings, and almost always fragile
• Non-asbestos fibre-cement sheets — modern replacements that are also fragile and degrade with age
• Rooflights and skylights — frequently hidden by paint, dirt, algae or moss, so they look identical to the surrounding sheet from above
• Glass — including wired and patterned glass in old roofs and canopies
• Old liner panels — thin internal panels that will not support a person
• Wood wool slabs — used as roof decking and prone to rot and water damage
• Corroded metal sheets — steel and aluminium profiled sheeting that has rusted or thinned at the fixings and laps

Two situations cause the majority of deaths. The first is simply walking on or near fragile materials. The second is unguarded or painted-over rooflights — a worker steps onto what they assume is solid sheeting and goes straight through. Both are entirely preventable.

The Legal Framework: Work at Height Regulations 2005

All work on or near fragile roofs is governed by the Work at Height Regulations 2005, enforced by the Health and Safety Executive (HSE). The regulations place a clear hierarchy of control on whoever plans and carries out the work. You must work down this hierarchy in order — you do not jump to harnesses because it is convenient, you only rely on them when higher controls are not reasonably practicable.

1. Avoid work at height where possible

The first duty is to avoid going onto the roof at all if the task can be done another way. Can the work be carried out from the ground or from inside the building? Options include working from below, using a mobile elevating work platform (MEWP) or cherry picker to reach the work from outside the roof, using long-reach tools and inspection cameras, or carrying out gutter and rooflight cleaning with extending lances. A surprising amount of inspection and maintenance work can be completed without anyone setting foot on a fragile surface.

2. Prevent falls

Where you must access the roof, the next duty is to prevent anyone falling. This means proper access and a working platform that spreads the load, plus protection against falling from the edge and through the surface. Practical measures include staging, crawling boards and roof ladders that spread the load across the load-bearing members, perimeter edge protection (guardrails or scaffold), and covering or guarding every rooflight. The aim is that even if someone slips, there is nothing they can fall from or through.

3. Minimise the consequences

Only where falls cannot be fully prevented do you move to minimising the distance and consequences of a fall. This includes safety nets slung beneath the work area, soft-landing systems (air bags or bean bags) below fragile sheets, and personal fall-arrest systems — harnesses and lanyards — as a genuine last resort. A harness is worthless without a suitable anchor point and a written rescue plan: a worker left suspended in a harness can suffer suspension trauma within minutes.

Planning and Risk Assessment Before You Go Up

Most fragile-roof deaths trace back to a job that was never properly planned. Before anyone goes near the roof, carry out a written risk assessment and method statement (RAMS) specific to that building. Establish the roof construction, the age of the sheets, and whether asbestos is present. Identify every rooflight — count them from inside if you can, because from above they may be invisible under decades of paint and moss. Decide the access method, the platforms and load-spreading boards you will use, the edge protection, and the rescue plan. Brief everyone on site before work starts.

Staging, Crawling Boards and Supported Platforms

You must never put your weight directly on a fragile sheet. Working platforms, staging and crawling boards must be long enough and positioned to span the load-bearing members — the purlins or rafters — so your weight is carried by the structure, not the sheeting. A single board is not enough: you need a leapfrogging set so you always have a supported surface ahead of you and never step onto bare sheet. Roof ladders used on pitched roofs must be properly secured at the ridge and must spread the load rather than concentrate it.

Platforms must be inspected before use, kept clear of debris, and never overloaded with materials. On larger jobs a fully boarded, fully decked staging system is far safer and faster than constantly repositioning individual crawling boards.

Edge Protection, Rooflight Guarding and Covers

Perimeter edge protection — guardrails, toe boards or a scaffold edge — must be in place wherever there is a risk of falling from the roof edge. Equally important is protecting against falls through the roof. Every rooflight in the work area should be guarded or covered. Options include fixed covers strong enough to bear a person's weight, purpose-made rooflight screens or cages fitted from below, or guardrails surrounding each rooflight. Covers must be securely fixed so they cannot be dislodged or accidentally moved, and clearly identifiable. Loose sheets simply laid over a rooflight are not acceptable — they slide.

Signage, Permits, Competence and Supervision

Fragile-roof areas should be signed at the access points so anyone arriving on site understands the risk. Many sites operate a permit-to-work system for roof access, which forces a check that controls are in place before anyone goes up. The people doing the work must be competent — trained and experienced in fragile-roof working — and adequately supervised, particularly where younger or less experienced workers are involved. Solar installers in particular often work on older commercial and agricultural roofs where fragile sheeting is the norm, and the same controls apply to them as to roofers.

Weather

Weather sharply increases the risk on any roof, and on fragile surfaces it can be decisive. Wet, frosty or mossy sheets are slippery; wind makes balance and handling boards dangerous; and low light or glare hides rooflights. Build weather limits into your method statement and be prepared to stop work. No deadline justifies sending someone onto a fragile roof in conditions that make a fall more likely.

The Special Case: Asbestos-Cement Roofs

Asbestos-cement sheeting is both fragile and a health hazard, so it demands extra care. Any cement roof sheet on a building from before the year 2000 should be presumed to contain asbestos unless testing proves otherwise. The fall risk is the immediate killer, but breaking, cutting or dropping the sheets also releases asbestos fibres. Most work on asbestos-cement sheets falls under non-licensed asbestos work, which still requires proper controls: trained workers, the right RPE and PPE, methods that avoid breaking the sheets, and correct disposal of any waste. Never walk on asbestos-cement sheets and never break or smash them to clear access.

Quick Reference: Fragile Roof Hazards and Controls

The Hierarchy at a Glance