Torch-On Membrane Roofing & Waterproofing SWMS
SWMS variants reference your state’s WHS legislation. Instant download after payment.
Torch-on membrane work combines an open flame with a solvent-primed substrate and an operator who is working at a roof edge, walking backwards. Three characteristics separate it from other hot work. The flame is applied continuously over a large area rather than at a point, so the ignition opportunity is not localised. Bitumen primer is solvent-based and its vapour is heavier than air and flammable, so it pools in upstands, box gutters, penetrations and parapet junctions — which are exactly the details the torch is brought to. And most dangerous of all, fire enters the structure through penetrations, laps and parapet cavities and smoulders unseen.
That last mechanism is why torch-on burns buildings down. The roof looks finished, the crew packs up and leaves, and the building ignites hours later. The control is a **continuous fire watch of at least 60 minutes after the last flame, with a further inspection at least 60 minutes after that** — and the crew does not leave site until it closes. Where the substrate is combustible, or a cavity, parapet or timber deck cannot be visually cleared, torch-on is simply not the appropriate method and a self-adhesive, cold-applied or induction-welded system must be substituted. That substitution is an elimination control and it is the first question this SWMS asks. Covers priming, torching, laps, upstands, penetrations and terminations on roofs, podiums, planter boxes, balconies, plant decks and below-grade tanking. Authored for New South Wales. Regulator: SafeWork NSW.
Hazards identified
14 hazards covered, sorted by priority.
The building ignites hours after the crew has packed up and gone home
Fall from a roof while walking backwards with a lit torch
Fall through a skylight, roof light or unmarked penetration
Fire reaching occupants, adjoining property or the structure below
Catastrophic cylinder failure in the work area
Flash fire or jet flame from a degraded hose, regulator or connection
Ignition of vapour pooled in the exact upstand the torch is brought to
Electrocution from roof plant, conduit or an overhead line at the edge
Deep burns from flame, hot bitumen or a heated roll — bitumen adheres and keeps burning
Head or crush injury to persons below from a dropped torch, cylinder or roll
Respiratory exposure for an operator working directly over the plume
Heat illness on an unshaded roof, compounded by flame-resistant clothing and radiant heat
Fall from a ladder while carrying cylinders, rolls or tools
Musculoskeletal injury handling rolls and cylinders on a hot, uneven roof
Control measures
Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.
- 1Substitute a self-adhesive, cold-applied or induction-welded membrane wherever the substrate is combustible or a cavity cannot be visually cleared — torch-on is not appropriate over a timber deck, an open parapet cavity or an unsealed penetration.
- 2Seal all cavities and protect penetrations, upstands and parapet junctions with non-combustible sheeting before any flame is lit.
- 3Maintain a dedicated fire watch — not the torch operator — for a minimum of 60 minutes after the last flame, with a further inspection at least 60 minutes later, and do not leave site until it closes.
- 4Issue a hot work permit that requires the substrate to be verified non-combustible before the permit is granted, and close it only after the full fire watch.
- 5Install perimeter edge protection to the full working perimeter before any membrane work starts, and sequence work away from edges rather than toward them — the operator works backwards.
- 6Cover every skylight, roof light and penetration with fixed, labelled covers, and work from platforms or crawl boards spanning onto structural members rather than onto fragile sheet.
- 7Remove all combustible material from within 6 m of the flame — packaging, offcuts, primer rags — and keep extinguishers and a charged hose at the work face.
- 8Locate LP Gas cylinders outside the heat-affected zone, upright, secured, shaded, with in-date hose and regulator, and turn them off at the cylinder valve at every break rather than at the torch.
- 9Leak test every connection with soapy water at each set-up — never a flame — and never leave a torch lit or laid on the membrane.
- 10Separate priming and torching in time and space, observe the manufacturer's drying time, and ventilate upstands and box gutters — primer vapour sinks into the details the torch must reach.
- 11Isolate and prove de-energised any roof-mounted plant, conduit or cabling in the work area; energised electrical work is prohibited under Part 4.7 Division 4, sections 154 and 157 unless de-energisation is not reasonably practicable.
- 12Notify the building manager and occupants, arrange fire detection isolation with documented reinstatement at the end of each shift, and advise when the fire watch closes.
- 13Ensure all workers hold a current White Card (CPCCWHS1001), are trained in LP Gas hot work, and are trained in fall arrest use and rescue where a harness is relied upon.
- 14Consult workers on WHS matters affecting them per Section 47 of the WHS Act 2011 (NSW), record the consultation, and review whenever the substrate, product, method or building occupancy changes, after any incident, or at minimum every 12 months.
Applicable Codes of Practice
The benchmark for roof edge protection, fragile surface control, penetration covers and roof access.
The benchmark for the solvent-based primer and LP Gas as hazardous chemicals, including vapour control and ignition control.
Cylinder storage, securing, separation distances, hose and regulator condition, leak testing and keeping cylinders out of the heat-affected zone.
The materials, design and installation requirements for the membrane system, including laps, upstands, terminations and falls.
Harness, lanyard and anchorage selection and use where fall arrest is relied upon at a roof edge or fragile surface.
The benchmark for construction-phase risk management, exclusion zones below the work and coordination with occupants.
High-Risk Construction Work triggered
Torch-on is applied on roofs, podiums, plant decks and balconies where a fall from an edge, through a fragile surface or through a penetration exceeds 2 m — and the operator works backwards with a lit torch.
LP Gas and solvent-based primer vapour create a flammable atmosphere, and the vapour is heavier than air so it pools in the upstands, box gutters and penetrations the torch is brought to.
Roof-mounted plant, conduit and cabling, and overhead lines at the roof edge, are worked on or near during membrane application.
Torch-on membrane work is high risk construction work under Section 291 of the WHS Regulation 2025 (NSW), so a SWMS must be prepared before work commences (Section 299), kept readily accessible, reviewed as necessary (Section 302), and given to the principal contractor if one is appointed. Part 4.4 requires the risk of a fall to be managed with edge protection as an engineering control ahead of any reliance on a harness. Energised electrical work is separately prohibited under Part 4.7 Division 4, sections 154 and 157 unless de-energisation is not reasonably practicable — convenience is never a valid reason. Critically, the primary duty of care at Section 19 of the WHS Act 2011 (NSW) extends to building occupants and adjoining owners exposed to a fire started by this work, and a concealed cavity fire that ignites hours after the crew leaves is foreseeable, not freak. A fire, a fall from height or a serious burn is a notifiable incident under Sections 35–38 and is prosecuted as a Category 1 or Category 2 offence, with the most serious breaches carrying imprisonment for individuals.
Who this is for
- →Roofing and waterproofing contractors applying torch-on bituminous membrane to roofs, podiums, planter boxes, balconies and plant decks.
- →Remedial and rectification contractors re-membraning existing roofs and podiums over occupied buildings.
- →Torch operators and their fire watch, and supervisors issuing and closing hot work permits.
- →Builders and principal contractors coordinating hot work over occupied or fitted-out buildings, including fire detection isolation.
- →WHS managers and HSE advisors responsible for hot work permits, fire watch discipline and roof edge protection.
What you receive
- ✓A complete, editable Safe Work Method Statement authored for New South Wales — the WHS Act 2011 (NSW), the WHS Regulation 2025 (NSW) and SafeWork NSW as regulator.
- ✓14 identified hazards with initial and residual risk ratings on a 5x5 matrix, each with controls ordered through the full hierarchy — eliminate, engineer, administrative, PPE.
- ✓The concealed cavity fire control set — the mechanism that burns buildings down hours after the crew has left — with the substitution question asked first.
- ✓A defined fire watch regime: a minimum 60 minutes continuous after the last flame, a further inspection at least 60 minutes later, and the crew not leaving until it closes.
- ✓The primer vapour control set built on the fact that solvent vapour is heavier than air and pools in the exact upstands and box gutters the torch is brought to.
- ✓LP Gas controls to AS/NZS 1596 — cylinder location outside the heat-affected zone, leak testing with soapy water never a flame, and shut-off at the cylinder not the torch.
- ✓The full high risk construction work breakdown — falls over 2 m, contaminated or flammable atmosphere and energised electrical — with the reason each category applies, and the Part 4.7 prohibition stated correctly for NSW.
- ✓A PPE matrix mapping each task to the required equipment and Australian Standard, emergency procedures covering roof fire, cavity fire, LP Gas leak and bitumen burns, and a worker sign-on table.
- ✓Microsoft Word (.docx) format, unbranded, editable fields for PCBU, ABN, site, prepared by, reviewed by, approved by and review date.
Worked example
A crew re-membranes a podium over an occupied basement carpark on a Friday afternoon. The deck is concrete, so the substrate box on the permit gets ticked. What nobody looks at is the parapet: a rendered blockwork upstand with a cavity behind it and a timber batten screwed inside for the coping. The torch runs up the upstand to seal the membrane, and heat goes through the joint into the cavity and finds the batten. Nothing happens. The membrane looks perfect. The crew does a fifteen-minute look-around because it is Friday and the traffic is bad, and they go home. At about nine that night the batten — which has been smouldering for five hours in a cavity nobody can see into — reaches the ceiling void. This SWMS stops it in two places. The substitution question comes first: a cavity that cannot be visually cleared means torch-on is the wrong method, and the parapet gets a self-adhesive detail. And if the flame is used, the fire watch is 60 minutes continuous plus an inspection 60 minutes after that, and the crew does not leave until it closes.
Related legislation
- Work Health and Safety Act 2011 (NSW) — Section 19 primary duty of care; Section 47 consultation; Sections 35–38 notifiable incidents.
- Work Health and Safety Regulation 2025 (NSW) — Section 291 (high risk construction work) and Section 299 (preparation and content of a SWMS), with review under Section 302.
- Work Health and Safety Regulation 2025 (NSW) — Part 4.4 (falls): the duty to manage the risk of a fall with edge protection as an engineering control ahead of any reliance on a harness.
- Work Health and Safety Regulation 2025 (NSW) — Part 4.7 (electrical), including the prohibition on energised electrical work at Division 4, sections 154 and 157, for roof-mounted plant and services.
- AS/NZS 1596 (The storage and handling of LP Gas), AS 4654.1 and AS 4654.2 (Waterproofing membranes for external above-ground use), and AS/NZS 1891.1 and 1891.4 (fall-arrest systems).
Frequently asked questions
Is a 60-minute fire watch really necessary on a concrete deck?
The deck is not the risk — the details are. Fire enters through penetrations, laps and parapet cavities and smoulders in whatever is behind them: battens, insulation, old membrane, debris. A concrete substrate tells you nothing about the cavity behind a rendered upstand or the timber inside a coping. The watch is a minimum of 60 minutes continuous after the last flame, with a further inspection at least 60 minutes after that, and the crew does not leave until it closes. That regime exists because the fires that destroy buildings after torch-on work start hours after the roof looked finished.
When should we not use torch-on at all?
Whenever the substrate is combustible, or a cavity, parapet or timber deck cannot be visually cleared and sealed. That is an elimination control and it is the first question this SWMS asks, ahead of any discussion about permits and watches. A timber deck, an open parapet cavity or an unsealed penetration means a self-adhesive, cold-applied or induction-welded system is the correct method. Substituting the method removes the ignition source entirely; every other control just manages it.
Why does the SWMS separate priming from torching?
Because solvent primer vapour is heavier than air and flammable, so it sinks and pools — in upstands, box gutters, penetrations and parapet junctions. Those are precisely the details the torch has to reach. Priming and torching in the same pass brings an open flame to a pooled vapour in a confined detail. The controls are to prime and torch as separate operations separated in time and space, observe the manufacturer's drying time, ventilate enclosed details, and confirm a detail is dry before any flame approaches it. A water-based primer removes the problem where the specification allows.
The roof is only 2.5 m up. Is a SWMS still required?
Yes. A risk of a person falling more than 2 m is a high risk construction work category at Section 291, and 2.5 m is more than 2 m — but the more useful point is that height is not the only trigger here. The flammable atmosphere created by LP Gas and primer vapour is its own category, and roof-mounted plant or an overhead line at the edge engages the energised electrical category. Any one of those requires a SWMS under Section 299. Low roofs also tend to have the worst edge protection, because they feel safe.