I’ve wondered the same thing about synthetics, especially with our Midwest winters. I had a section of my garage roof done with synthetic underlayment about 8 years ago—nothing fancy, just basic shingles over it. It’s held up okay so far, but I did notice last winter when I was up there clearing off some branches that the edges felt a little crispy. Not cracking yet, but definitely not as flexible as when it went down. The installer swore it would outlast felt by a mile, but now I’m not so sure.
On my main house, I stuck with felt because it was cheaper and honestly, I figured if something went wrong, patching would be easier (and it has been). But you’re right—tearing off old felt is a nightmare. It sticks like glue after a few years and makes for a messy job.
I keep hearing that synthetics are supposed to be “breathable” and better at keeping moisture out, but if water pools on a low-slope roof, does it really matter what’s underneath? Maybe the real issue is how well the roof sheds water in the first place. Has anyone tried those peel-and-stick membranes instead? They’re pricier but supposedly handle standing water better.
I’m always looking for ways to save money without cutting corners too much. If synthetic really does get brittle in cold weather, maybe it’s not worth the extra cost here. Or maybe there’s a brand out there that actually holds up better in freeze-thaw cycles? Would love to hear if anyone’s found one that doesn’t turn into plastic wrap after a few winters...
