HSG33 explained: a UK roofer's guide to HSE roof work guidance in 2026

HSG33 is the most important document a UK roofer will read this year, and most roofers have never opened it. It is the Health and Safety Executive's controlling guidance for all UK roof work — a 142-page document covering everything from fragile roofs through to edge protection, ladder access, scaffolding to eaves, weather restrictions, and what HSE inspectors look for after an accident. This guide is the plain-English version: what HSG33 actually says, what it means for a working roofer in 2026, and the specific paragraphs HSE inspectors quote in prosecutions.

What HSG33 is and why it matters

HSG33 is the title of the HSE's "Health and safety in roof work" publication, currently in its 5th edition. It is not a law in itself; the underlying laws are the Health and Safety at Work etc. Act 1974, the Construction (Design and Management) Regulations 2015, and the Work at Height Regulations 2005. HSG33 is the HSE's official guidance on how to comply with those laws when doing roof work.

Crucially, HSG33 carries an authority that ordinary "guidance" does not. The HSE explicitly says that following HSG33 will normally be enough to meet legal requirements; conversely, if your method falls short of HSG33, you must be able to demonstrate that your alternative is at least as safe. In practice, HSE inspectors and courts treat HSG33 as the working benchmark. If a roofer is prosecuted after a fatal fall, the prosecution will quote chapter and paragraph from HSG33 to show what the duty-holder should have done.

The headline statistic in the document is the one every roofer should know: roof work accounts for approximately 25% of all UK construction industry fatalities. Falls through fragile roofs and falls from roof edges together account for the majority of those deaths. HSG33 exists because roof work is, statistically, the most dangerous activity on a typical UK construction site.

The fragility presumption

The single most important principle in HSG33 is what the document itself calls the fragility presumption. The exact wording is that "all roofs should be treated as fragile until a competent person has confirmed they are not." This is not aspirational language; it is the working assumption every operative is expected to start from.

The materials most commonly responsible for fragile-roof falls are: fibre-cement (commonly called "asbestos cement") sheets, particularly those that have weathered or are more than 10 years old; non-reinforced rooflights, including those that have been painted over or covered in moss; weathered metal sheeting where corrosion has reduced strength; glass roofing of any age; and old timber boarding, particularly where rot may be present.

The HSE makes a specific point that paint colour is not a safety control. Many old asbestos-cement rooflights have been painted to match the surrounding sheeting and become invisible to an operative on the roof. HSG33 is explicit: a competent person must confirm fragility from a survey, drawings, or other reliable source before any operative is asked to step on the roof.

Where fragility cannot be excluded — and on most older industrial and agricultural buildings, it cannot — HSG33 sets out a hierarchy of how to deal with it, covered in the next section.

The hierarchy of control: avoid, control, communicate

HSG33 sets out a three-step hierarchy that runs through every part of the document: avoid working at height where reasonably practicable, control the residual risk through engineered measures, and communicate the residual risk to everyone affected.

Avoid. The first question is always whether work can be done from below. A MEWP positioned beneath the roof, with the operative working from the basket, eliminates the fall risk entirely. Repair work carried out from inside the roof void where the structure permits avoids the risk. Inspection by drone or extending pole eliminates physical access. The HSE expects this question to be asked first and the answer recorded. "We are using a scaffold" is not an answer until the prior question has been addressed.

Control. Where avoidance is not reasonably practicable, engineered controls are applied in a specific order: collective protection before personal protection. Collective protection means barriers, edge protection, safety nets, and soft-landing systems — controls that protect anyone present without each individual having to do anything. Personal protection means harnesses, lanyards and fall arrest — controls that depend on the individual being correctly trained, equipped and disciplined.

HSG33 is explicit that collective protection is preferred because it does not depend on operative behaviour. A guardrail that is in place protects everyone on the platform; a harness only protects the operative who clips it on correctly. Where both can be used, both are used; where only one is reasonably practicable, collective is preferred.

Communicate. The third step is making sure everyone on site, not just the roofers, knows about the fragile areas, the safe walking routes, the rescue plan, and the stop conditions. This means warning notices on every approach to fragile material, clear marking on drawings and method statements, toolbox talks at the start of each shift, and a daily briefing on the day's specific hazards. HSE inspectors look for evidence that this communication actually happened — signed toolbox talks, dated briefing records, photographs of warning signage in place.

Edge protection by roof angle

HSG33 sets out edge protection requirements that scale with the roof angle. The thresholds matter because they determine what counts as adequate protection in law.

Pitched roofs up to 30 degrees. A scaffold to eaves height with continuous edge protection — top guardrail at 950 mm minimum, intermediate guardrail with no more than a 470 mm gap, toeboard at 150 mm minimum — is the standard. Roof ladders or crawling boards spread the operative load on the slope.
Pitched roofs 30 to 45 degrees. The above plus secondary edge protection up the slope or roof ladders fixed in position. A continuous handrail at eaves alone is not sufficient because an operative who slips on a 40-degree slope will not be stopped by it before reaching the edge.
Pitched roofs above 45 degrees with a falling height greater than 5 metres, or above 60 degrees at any height. Eaves edge protection is no longer adequate as a sole control. Higher-level work platforms must be installed, or fixed-position crawling boards with operative restraint must be used. This is the threshold above which a typical eaves scaffold and a roof ladder is not enough.
Flat roofs. Edge protection is required around the perimeter where there is a fall risk. Where this is not reasonably practicable around the entire perimeter, a clearly marked physical barrier (not a painted line) at least 2 metres from the edge defines a safe working area. This is acceptable only where supervision is high and discipline is strict.

For terraced and attached properties, HSG33 makes a specific point that edge protection is required on every elevation that has a fall risk, including the rear, gables, and party-wall returns. This is repeated explicitly because the HSE has prosecuted multiple small roofers who erected a scaffold to the front of a terraced house only, with the operative falling off the rear or gable. There is no half-measure here: every fall-risk elevation needs protection.

Fall arrest as the last line of defence

Where collective protection cannot reasonably be installed, personal fall arrest is the last line of defence. HSG33 sets out specific requirements for fall arrest systems.

Anchor points must be rated and tested for fall arrest. A lanyard clipped to a guardrail, a toeboard, or a random scaffold tube of unknown rating is not a fall arrest system. Anchor points are typically rated to 12 kN minimum, recorded in an anchor register, and inspected before use.

The lanyard length and free-fall distance must be calculated so the operative does not reach the ground or any lower obstruction before the fall is arrested. An energy-absorbing lanyard typically extends by up to 1.75 metres in arrest, plus the body length of the operative, plus the original lanyard length. The fall clearance below the anchor must exceed this total by a safety margin.

A rescue plan must be in place before any work using fall arrest commences. HSG33 references the risk of suspension trauma — a worker hanging in a harness becomes incapacitated within minutes if not recovered. The plan must be specific, the rescue equipment must be on the working lift, and the nominated rescuer must be identified at the pre-start briefing.

Daily pre-use checks of harness, lanyard and connectors are carried out by the wearer. Thorough examination by a competent person every six months is required, recorded on the harness tag and in the inspection register. Damaged equipment is destroyed (cut through the webbing) when removed from service to prevent accidental reuse.

Weather, wind and stop conditions

HSG33 addresses weather restrictions for roof work. The thresholds are set in the supporting Work at Height Regulations technical guidance, and the standard convention used by major UK roofing contractors is the Beaufort scale.

Beaufort Force 5 (19 mph sustained). Stop work at height on the roof slope or near any unprotected edge. Wind at this level affects an operative's balance.
Beaufort Force 6 (23 mph sustained). Stop all roof work, including work behind edge protection. Temporary works become unstable above this threshold.
Lightning within 10 km of the site. Stop all work at height immediately. Resume only when the storm is confirmed past.
Heavy rain or icing. Stop slope work where footing is compromised. Working surfaces are cleared of ice, snow and standing water before work resumes.

Wind speed is monitored using a handheld anemometer at working height, with readings taken at the start of each shift and every two hours, recorded on the daily inspection sheet. The forecast is reviewed at shift start; activity is rescheduled if the forecast exceeds the threshold.

Safe access to and from the roof

HSG33 dedicates a section to access, on the basis that getting onto and off the roof is a high-risk transition. The preferred access methods, in order of preference, are: stair access via a stair tower in the scaffold; ladder access via a tied ladder set at 1:4 angle and projecting 1 metre above the landing; and MEWP access where the building geometry permits.

Ladders used for access only must be tied at the top, footed during ascent, and removed or barred off outside working hours. Free-standing ladders are not acceptable for roof access. Stepladders are not acceptable for roof access at any height.

Roof ladders for working position must be hooked over the ridge with the hook fully engaged on the opposite slope. A secondary tie is required where the slope exceeds 30 degrees. The roof ladder is inspected before each use under PUWER 1998 and removed from the roof at the end of each shift.

Falling objects and ground protection

HSG33 covers the risk to people and property below the roof, which is often more visible to the public than the operative's own risk. The standard controls are:

Ground-level exclusion zone directly below any elevated work, with Heras fencing or equivalent hard barriers and signage. The zone is increased on windy days to account for wind-blown debris.
Toeboards on every platform from which work is carried out (150 mm minimum) to prevent components rolling off the edge.
Debris guards or brick guards on every lift where there is a risk of small components falling between the guardrails.
Materials passed by hand within the working footprint. No throwing of components between levels at any height, regardless of distance.
End-of-shift visual check by the supervisor for loose materials, recorded on the daily inspection sheet.

Particular care is required where the roof overhangs a public footpath or a busy road. Scaffold fans or debris netting may be appropriate. Where work is on a school, hospital, or residential building, the timing of work is planned around occupation patterns where possible.

Specific topics HSG33 covers in detail

The full HSG33 publication contains detailed sections on a range of specific topics that working roofers should know about.

Fragile rooflights and how to identify them. Rooflights manufactured before 2014 are particularly likely to be fragile. Even modern rooflights can become fragile through UV exposure and weathering. The HSE recommends that all rooflights are treated as fragile in the absence of recent test certification.

Valley walking. Cleaning valley gutters on industrial roofs has caused multiple fatalities. The HSE-recommended control is a "valley walker" — a mesh-covered protective frame that moves along the valley with the operative, preventing a fall through the adjacent fragile material.

Refurbishment and re-roofing. The phase between stripping the old covering and installing the new is high-risk. The strip exposes the operative to the structure (potentially with rot or insect damage), changes the loading on the roof structure, and produces large volumes of waste that must be moved off the roof. HSG33 sets out specific controls including structural review where significant areas are stripped at once.

Ancillary work. Adjusting TV aerials, installing solar PV panels, cleaning gutters, painting fascias — all of these are roof work in the eyes of the HSE, regardless of the trade of the operative. Many fatalities involve workers who were "not really roofers" doing short-duration roof tasks without proper preparation.

What HSE inspectors actually look for

If the HSE attends a site after an accident or for a planned inspection, the inspector will look for specific evidence of HSG33 compliance.

Documented risk assessment that names HSG33 and the fragility presumption explicitly.
Method statement that follows the avoid-control-communicate hierarchy.
Pre-start survey or equivalent identifying fragile areas, rooflights, asbestos-containing materials, and substrate condition.
Edge protection in place and inspected, with the inspection record on site.
Daily wind speed log with anemometer readings.
Toolbox talk records signed by all operatives present.
Competence cards (CSCS, NVQ certificates, asbestos awareness) for every operative on site.
Harness inspection records and a current rescue plan if fall arrest is in use.
Hot works permit for any open-flame activity, with fire-watch records.

The roofer who can produce all of the above on demand is rarely prosecuted, even after an accident, because the documentation demonstrates that the work was planned and supervised properly. The roofer who cannot produce this documentation is prosecuted regardless of how skilled the actual work was, because the law requires the planning to be evidenced, not just done.

The practical takeaway

HSG33 is not a document to read once and file. It is the working benchmark for every UK roofing job and every piece of paperwork that supports it. The roofers who treat HSG33 as their starting point — when writing RAMS, briefing operatives, planning access, choosing edge protection, setting wind stop conditions — are the ones who pass HSE inspections, win commercial work, and stay out of court.

The full document is free to download from the HSE website. Read the executive summary at minimum. Skim the sections that match the work you actually do. Reference it explicitly in your RAMS. Train your operatives to know the fragility presumption and the wind thresholds. The cost of doing this is a few hours of reading and a small amount of administrative discipline. The cost of not doing it is occasionally measured in convictions, fines, and lives.

If you want roofing RAMS that align with HSG33, the fragility presumption, the hierarchy of control, the right Beaufort thresholds, and the right edge protection by roof angle, this is exactly what Complys generates. Pick the roofing trade, fill in the brief, and the document is in your hands in under three minutes.