Permits to Work · Best Practice · Construction
Permit to Work — Roof Access
The Roof Access Permit authorises personnel to access roof areas and confirms that fragile surface assessments have been completed, edge protection or harness systems are in place, and weather conditions are acceptable. It identifies safe access routes, demarcation of fragile areas, and any restrictions on the number of workers permitted on the roof at one time.
Last reviewed: 29 March 2026 — This guide reflects UK law as of this date. WAH Regs 2005 remains current with no amendments enacted as of 29 March 2026. Next scheduled review: 29 March 2027.
| Legal basis | Work at Height Regulations 2005 (WAHR) + CDM 2015 Schedule 3 + HSE guidance INDG284 (fragile roofs) |
| Fragile roofs | Asbestos cement sheets, fibre cement sheets, translucent rooflights, corroded metal decking, and any roof covering that cannot support the weight of a person plus any load they are carrying |
| Control hierarchy | Avoid roof access where possible; if unavoidable: platforms and stagings first, then crawl boards/duck boards, safety nets below, personal fall arrest (harness) as last resort |
| Edge protection | All exposed edges must have edge protection complying with Schedule 2 of WAHR 2005 — guard rail, mid rail, and toe board as a minimum |
| Falling objects | Exclusion zone at ground level below all roof work areas; toe boards, brick guards, or debris netting to prevent materials falling from roof edges |
| Weather restrictions | No roof access in wind speeds above 23 mph (force 6), during rain, hail, snow, or when surfaces are icy — unless specific controls are in place and documented |
1. Roof Access — Falls Through and Falls From
Roof work involves two distinct categories of fall hazard, each requiring different controls. Falls from a roof edge occur when a person working near the perimeter of a roof falls over the unprotected edge to the ground below. Falls through a roof surface occur when a person steps on a fragile roof covering — such as an asbestos cement sheet, a deteriorated fibreglass rooflight, or corroded metal decking — and the material gives way beneath their weight. Both types of fall are frequently fatal.
Falls through fragile roof surfaces are particularly dangerous because the person typically falls the full height of the building interior without obstruction. On industrial buildings with asbestos cement roofs, the fall distance from roof level to floor slab can exceed 10 metres. There is no opportunity to arrest the fall once the material has fractured. The person drops through the hole created by their body weight and the broken sheet offers no handhold or means of self-rescue.
The Work at Height Regulations 2005 require that work at height is avoided where reasonably practicable, and where it cannot be avoided, that it is properly planned, supervised, and carried out using appropriate equipment. For roof access, the regulations impose a clear hierarchy of control: collective protection measures (platforms, guard rails, safety nets) take priority over personal protection (harnesses and lanyards). A permit to work for roof access ensures that the roof surface has been assessed, the correct controls are in place, and the work is formally authorised before anyone sets foot on the roof.
Every roof is potentially fragile until proven otherwise
The assumption must always be that a roof surface is fragile unless a competent person has inspected it and confirmed that it is capable of supporting the weight of persons and any equipment they are carrying. This applies to roofs that appear solid from above — asbestos cement sheets, for example, look and feel rigid but will fracture instantly under point loading. Rooflights that were translucent when installed may have become opaque with age and be indistinguishable from the surrounding roof sheets. Corroded metal decking may have lost structural capacity while appearing intact from the upper surface. No one should walk on any roof surface until its load-bearing capacity has been confirmed.
2. Roof Access PTW — Required Content
The roof access permit to work must document the assessment of the roof surface, the access arrangements, the fall prevention and fall arrest measures in place, and the controls for falling objects and weather conditions. The following table sets out the fields that must be completed on every roof access permit.
| Field | Required content |
|---|---|
| Roof surface assessment | The type of roof covering (profiled metal, asbestos cement, concrete, membrane, tiles), its condition, and whether it is classified as fragile. The assessment must be carried out by a competent person and must identify all rooflights, valleys, gutters, and areas of deterioration. Where the roof is fragile or contains fragile elements, the specific locations must be marked and the control measures for working near or over those areas must be stated. |
| Access equipment | The means of access to and from the roof (internal staircase, external ladder, scaffold access tower, MEWP). Ladders must comply with BS EN 131 and must be secured at the top. Access towers must be erected by a competent person. The access point must be defined and no alternative access route may be used without re-assessment. |
| Edge protection | The type, location, and extent of edge protection in place at all exposed roof edges. Edge protection must comply with WAHR 2005 Schedule 2: a top guard rail at a minimum height of 950 mm, an intermediate guard rail, and a toe board at least 150 mm high. Where permanent edge protection is not installed, temporary edge protection must be erected before roof access is permitted. |
| Exclusion zone | The ground-level exclusion zone below the roof work area must be defined, marked, and enforced. The zone must extend a sufficient distance from the building perimeter to account for materials or debris falling from the roof edge. Physical barriers (not just signage) must be used to prevent pedestrians from entering the exclusion zone during roof works. |
| Weather check | A weather assessment must be carried out before each access to the roof. The permit must state the wind speed threshold at which work must stop (typically 23 mph / force 6), and must prohibit access when surfaces are wet, icy, or snow-covered unless specific additional controls (anti-slip footwear, treated surfaces) are documented and in place. |
| Fall arrest arrangements | Where personal fall arrest is required (as a supplement to collective protection or as a last resort where collective protection is not reasonably practicable), the permit must record the type of system (full body harness, shock-absorbing lanyard, inertia reel, horizontal lifeline), the anchor points being used, the competence and training of each user, and confirmation that all equipment has been inspected and is within its service date. |
| Rescue plan | A written rescue plan must be in place before any work at height on a roof commences. The plan must describe how a person who has fallen and is suspended in a harness, or who has fallen through a fragile surface, will be rescued. The rescue must be capable of being carried out within the suspension trauma window (typically 15 to 20 minutes). The plan must identify the rescue equipment, the trained rescuers, and the location of the equipment relative to the work area. |
| Supervision | The name of the person responsible for supervising the roof works, their competence, and their physical location during the works. The supervisor must have direct line of sight or radio contact with all persons on the roof. For work on fragile roofs, the supervisor must be present at all times and must not be simultaneously supervising other work activities elsewhere on site. |
| Duration limit | The maximum permitted duration of the roof access. The permit must state the start time, the latest permitted end time, and the conditions under which work must cease before the end time (weather deterioration, change in site conditions). A new permit is required if the work extends beyond the stated duration. |
3. Common Mistakes
No roof surface assessment before access
Allowing workers onto a roof without a documented assessment of the roof surface is one of the most dangerous failures in construction. Roofs that appear solid can be fragile. Asbestos cement sheets, aged rooflights, and corroded metal decking all fracture without warning under point loading. The assessment must be carried out by a competent person who inspects the roof from below (where possible) and above before any access is permitted. Without this assessment, the permit cannot be issued.
Relying on harnesses without a rescue plan
A fall arrest harness prevents a person from hitting the ground, but it does not prevent injury. A person suspended in a harness after a fall is at risk of suspension trauma (orthostatic intolerance), which can become life-threatening within 15 to 20 minutes. If there is no rescue plan, no rescue equipment, and no trained rescuer available, the harness may save the initial fall but the person cannot be recovered in time. Every roof access permit that specifies harness use must have a corresponding rescue plan.
No exclusion zone at ground level
Materials, tools, and debris falling from a roof can cause fatal injuries to persons at ground level. An exclusion zone must be established below all roof work areas, extending a sufficient distance from the building perimeter to account for objects being blown outward by wind. The zone must be physically barriered — signage alone is insufficient because it does not prevent entry. Toe boards and debris netting at the roof edge provide additional protection but do not replace the ground-level exclusion zone.
Working on roofs in adverse weather without additional controls
Rain, ice, frost, and high winds all increase the risk of falls on roofs. Wet or icy surfaces reduce traction. Wind gusts can unbalance a worker, particularly when carrying materials or working near an unprotected edge. The permit must define weather thresholds and the work must stop when those thresholds are reached. Continuing to work in adverse conditions because the programme demands it is not an acceptable approach to managing the risk.
Rooflights not identified or protected
Rooflights are a leading cause of fatal falls through roofs. Older rooflights made from GRP (glass reinforced plastic) become opaque and brittle with age and can be difficult to distinguish from the surrounding roof sheets, particularly when covered with moss, dirt, or paint. Every rooflight must be identified during the roof survey, marked on a roof plan, and physically protected with covers or barriers that can support the weight of a person. Walking routes across roofs must be planned to avoid rooflights.
5. Frequently Asked Questions
What makes a roof fragile?▾
A roof is classified as fragile if it cannot safely support the weight of a person and any load they are carrying, together with any dynamic forces that may be applied (such as a stumble or slip). Common fragile roof materials include asbestos cement sheets, fibre cement sheets, GRP rooflights (particularly aged or UV-degraded panels), glass rooflights without walk-on rating, corroded metal decking, woodwool slabs, and any roof covering that has deteriorated due to age, weathering, or damage. A roof that was non-fragile when installed may have become fragile through deterioration. The only way to determine fragility is a competent assessment — visual inspection from above alone is not sufficient.
Can crawl boards be used as the sole means of fall prevention on a fragile roof?▾
Crawl boards (or roof ladders and duck boards) spread the load over a larger area and prevent point loading on fragile sheets. They are an important part of the control system for fragile roofs, but they are not sufficient on their own. Crawl boards must be used in combination with other measures: safety nets below the fragile surface to arrest a fall if a board shifts or a person steps off, or a personal fall arrest system (harness and lanyard) attached to a suitable anchor. The hierarchy of control requires collective protection (nets) before personal protection (harness), so nets should be the preferred secondary measure where they can be installed.
What wind speed should stop roof work?▾
There is no single statutory wind speed limit for roof work, but industry practice and most site rules set a threshold of 23 mph (force 6 on the Beaufort scale) as the point at which roof work should cease. At this wind speed, large branches move, umbrellas are difficult to control, and a person carrying a sheet material on a roof can be unbalanced. For work involving handling of large panels, sheeting, or membrane materials, a lower threshold may be appropriate. The permit must state the specific threshold that applies and the person responsible for monitoring wind conditions and calling a stop.
Is edge protection required on all four sides of a flat roof?▾
Edge protection is required at every point where a person could fall from the roof edge. On a flat roof, this means all exposed edges — not just the sides facing outward. Where the roof abuts a higher structure on one or more sides, edge protection is not required on those sides provided the abutting structure prevents a fall. On all other edges, Schedule 2 compliant edge protection (top guard rail at 950 mm minimum, intermediate guard rail, and toe board at 150 mm minimum height) must be in place before anyone accesses the roof. Rope and post systems may be acceptable for short-duration work provided they meet the Schedule 2 requirements.
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