I’ve seen that happen more than once with those “60-day” synthetics—marketing never mentions what 60 days in the sun really means. I had a job last July where the underlayment basically melted to the OSB, and it took us forever to scrape it off. Felt’s not perfect, but at least you know what you’re getting. Curious if anyone’s tried one of those newer “breathable” synthetics? I keep hearing mixed things, but haven’t seen one hold up to a real scorcher yet.
Yeah, I’ve run into that same mess with synthetics fusing to the deck—especially on south-facing slopes in July. The “breathable” ones are interesting, but I’m not convinced they’re worth the premium yet. Tried one last summer and it started curling at the seams after a week of 90+ temps. Felt’s got its flaws, but at least you know how it’ll behave when things heat up.
That curling at the seams sounds all too familiar. I tried one of those so-called “breathable” synthetics on a green roof install last August, thinking it’d be the magic bullet for moisture control. Instead, it shrank like a cheap T-shirt in the heat and we had to patch it up before the membrane even went down. Felt’s old-school, but at least you know it’ll lay flat if you get it covered quick. Still, I keep hoping someone will crack the code for something that holds up to both sun and foot traffic—hasn’t happened yet for me.
Felt’s old-school, but at least you know it’ll lay flat if you get it covered quick.
Funny thing, I’ve had the opposite luck with felt on a couple jobs—maybe it’s our wild temperature swings here in the Midwest, but I’ve seen it bubble up if there’s even a hint of moisture trapped underneath. The synthetics are hit or miss, though. Tried one brand last year that claimed “UV stable for 60 days.” Well, after three weeks in July sun, it was crispy as a cracker. Maybe the trick is just not leaving anything exposed too long… easier said than done when the weather won’t cooperate.
I hear you on the Midwest weather—one day it’s bone dry, next day you’re swimming. I’ve had felt do that bubbling trick too, especially if the crew’s rushing and there’s even a little dew left over. Once had to pull off half a roof because the felt wrinkled up like an old shirt after a surprise rainstorm. Not my favorite memory.
Synthetics are a mixed bag in my book. The UV claims always sound good until you actually test them in real life. I tried one of those “90-day exposure” rolls last summer, left it up for maybe four weeks while we waited for shingles, and it started getting brittle around the edges. Sun just eats that stuff alive, especially on a south-facing slope.
Honestly, I’ve started timing jobs so we’re not leaving anything exposed more than a couple days if I can help it. Not always possible, but it saves headaches. If weather’s unpredictable, I’ll double up on fasteners or even tarp over the underlayment at night. It’s more work, but beats redoing it when the wind picks up or the sun cooks it.