Building & renovation
How much propane for torch-applied roofing membrane?
How much propane and how many cylinders for torching bitumen membrane — from m² and kg/m² consumption.
Quick answer
Torch-down APP/SBS membrane is bonded with a propane torch, not adhesive in a tub. Consumption is typically 0.25–0.45 kg propane per m² depending on membrane thickness, ambient temperature and how fast the roofer moves. Formula: propane kg = area × kg/m². Worked example: 50 m² flat roof section at 0.35 kg/m² → 17.5 kg propane → 2× 11 kg cylinders (always keep a spare on site).
Advanced settings
Cylinders needed
2
- Propane needed
- 17.5 kg
- Approx. torch hours
- 8.8 h
Torch-applied bitumen membranes (APP/SBS) typically burn 0.25–0.45 kg propane per m² depending on membrane thickness, weather and operator pace. Cold or windy days increase use. Always ventilate and follow hot-work permits on occupied buildings.
How it works
Cold mornings and wind push consumption toward the high end; experienced crews on warm days can approach 0.25. This does not include membrane roll quantity — pair with our roof area calculator for m². Hot work permits, fire watch and torch roofing kit safety gear are non-negotiable on occupied buildings.
The propane is the cheap part of this job; the expensive part is what happens after you pack up. Torch work starts fires that do not show themselves for hours, smouldering inside a timber deck or behind an upstand where the flame was played against it — which is why the trade rule is to stop torching well before the end of the day and stay on site inspecting for at least an hour afterwards. Where the detail runs against anything combustible, the answer is not a careful flame: it is a self-adhesive or mechanically fixed detail at that junction, and torch only where there is mineral surface behind.
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Frequently asked questions
How many propane cylinders for 100 m²?+
At 0.35 kg/m²: 35 kg total → four 11 kg cylinders with one spare, or seven 5 kg camping cylinders (more swaps, less efficient). Budget 0.4 kg/m² in winter for the same area.
What burn rate for a roofing torch?+
Typical wide roofing burners use ~1.5–3 kg/h propane depending on flame setting. A 50 m² job at 0.35 kg/m² (17.5 kg) is roughly 6–12 hours of torch time — not one continuous hour; overlaps, roll changes and safety breaks add up.
Is 0.35 kg/m² realistic?+
It is a mid-range planning figure for standard 4 mm torch membrane in mild weather. Manufacturer courses sometimes cite 0.2–0.3 for skilled applicators; first-timers or thick mineral caps should use 0.4–0.45. Edit the field to match your last job log.
Propane vs gas cylinder for membrane?+
Professional torch roofing in Europe almost always uses propane (11 kg or 33 kg cylinders). MAP/Pro gas blends exist for plumbing torches but lack heat for wide membrane burners. Match regulator and hose to cylinder type.
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