torch-down can actually be a bit more forgiving on older or uneven decks
I’ll second that—my garage roof is about as flat as a pancake that’s seen better days, and torch-down was way less fussy than the peel-and-stick stuff I tried before. The fire part honestly freaked me out at first, but after watching my neighbor do his (with two fire extinguishers and a garden hose at the ready), it seemed doable. Just don’t try it on a windy day unless you like living dangerously... or enjoy explaining scorch marks to your insurance guy.
I get why folks like torch-down for tricky decks, but I’ve seen a few too many close calls with open flames on old wood. Self-adhered membranes might be fussier, but they’re a lot less stressful if you’re not used to working with a torch. Sometimes the extra prep is worth the peace of mind.
Torch-down always made me a bit nervous, honestly. I remember being on a job years ago—old warehouse roof, dry as tinder—and the guy next to me nearly set a joist smoldering just flashing in a corner. We caught it quick, but the smell stuck around for days. After that, I started looking harder at alternatives, especially on older buildings or anywhere with a lot of wood.
Self-adhered membranes can be finicky, no doubt. The first time I tried one, I thought I’d ruined the whole roll—sticky stuff everywhere, and if you miss your alignment, good luck pulling it back up without stretching or tearing. But once you get the hang of it, there’s a lot less stress about fire risk. Plus, some of the newer products have better UV resistance and flexibility than they used to.
Where it really gets interesting is when you’re thinking about adding green roof layers. Torch-down under a living roof? That’s a recipe for anxiety unless you’ve got an experienced crew and perfect conditions. Self-adhered or even cold-applied systems just feel safer when you’re stacking soil and plants on top—less chance of hidden hot spots or embers getting trapped under insulation or root barriers.
I get why torch-down is still popular for tricky details or odd-shaped decks—it’s hard to beat for waterproofing when done right. But if you’re not doing this every day, or you’re working solo, the peace of mind from a flameless install is worth the extra prep and patience. Especially when you think about insurance headaches if something does go wrong...
I’ve seen a few torch-down jobs where the char marks were still visible in the attic, so I get the nerves around open flame—especially on old wood. Have you ever run into issues with self-adhered membranes not sticking well in colder temps? That’s one thing I hear about a lot, especially up north.
I’ve actually run into that exact issue with self-adhered membranes not bonding well when it’s cold out. I’m in central New York, so we get plenty of those days where it barely creeps above freezing, and I’ve noticed the stick-down stuff just doesn’t grab like it should unless you’re really careful. Even when the packaging says “cold weather formula,” it still seems to need a good bit of sun or at least a heat gun to get a solid seal. I’ve had to go back and re-roll seams more than once because they started to lift after a cold snap.
Torch-down makes me nervous for the reasons you mentioned—old wood, hidden gaps, and just the general unpredictability of open flame. I watched a neighbor’s crew set off a small attic fire a few years back. They caught it quick, but it was enough to make me rethink using torch-down on my own place. The char marks you saw are no joke... once that wood’s been scorched, it’s never quite the same.
If you’re stuck between the two, I’d say self-adhered is safer but only if you can get the temps up or use some supplemental heat. Otherwise, you’re risking leaks down the line. I’ve heard some folks up north will store the rolls indoors overnight and only bring them out right before install, just to keep them pliable. Not always practical, but it helps.
For what it’s worth, I ended up going with a peel-and-stick underlayment plus a metal roof over it. More upfront cost, but zero open flame and no issues with adhesion since we waited for a warm stretch. Not everyone has that luxury with timing, though.
Curious if anyone’s tried those newer self-adhered products that claim to work down to 20°F? I’m skeptical, but maybe tech has improved since my last go-around.
