These are low-slope sections where a fully bonded asphalt surface is wanted and the surroundings tolerate an open flame — masonry parapets, non-combustible decks, and clear working space rather than timber, plant and stored material crowded up against the detail.
(214) 807-0414Request an assessmentTorch-down membrane
Torch-down membrane roofs, in North Texas settings.
Modified bitumen applied with an open flame. Effective, and with real constraints near parapets, plant and anything combustible.
The system
What torch-down membrane is, and where it is the wrong answer.
Torch-down is not a separate material. It is one of the ways modified bitumen is applied: the underside of the roll is melted with a propane torch as the sheet is unrolled, so the membrane bonds in its own molten asphalt. The alternatives to it are hot mopping, cold adhesive and self-adhered sheets, and they produce the same membrane.
Torching is the wrong method wherever the flame cannot be controlled — timber decks, close framing, ventilated cavities that carry heat sideways, occupied buildings where an ignition would be found late. Where those conditions exist the same membrane goes down cold or self-adhered and performs identically. The method is a means, not a virtue.
What an assessment looks at on this system
01
What the deck is made of, and what sits under it. An open flame over a combustible deck is a different job from the same detail over concrete, settled before a torch is lit.
02
The fire watch: whether one is planned, who holds it, and how long after the last roll it carries on. Asphalt smoulders quietly, and ignition is usually found well after the crew has stopped.
03
How the detail work at walls and penetrations will be done, since those are the points where the flame comes closest to something that is not roofing and cannot be moved.