That’s exactly what I’m worried about—once you’ve got two layers, it’s almost impossible to see what’s going on underneath until it’s too late. I get the appeal of saving on labor and disposal costs, but if you end up with hidden rot or sagging decking, isn’t that just a bigger headache down the line? Has anyone actually had luck with double-layer roofs in places with heavy rain or snow? I keep hearing mixed things, especially from folks in the Midwest.
Had a double-layer roof on my old place in Wisconsin—let’s just say it looked fine until one spring when the snow melted and I found a lovely patch of mushy plywood above the kitchen. The second layer hid all the warning signs. Sure, it saved me a few bucks up front, but tearing off two layers later was a pain (and pricier). If you get a lot of snow or rain, I’d be real cautious about skipping the full tear-off.
I went the “just add a layer” route on my last house because it seemed cheaper and faster. Regretted it after a couple years—ice dams started, and I couldn’t tell where the leaks were coming from. Ended up paying more to fix the mess. If I had to do it again, I’d rip it all off, even if it’s a pain.
Regretted it after a couple years—ice dams started, and I couldn’t tell where the leaks were coming from.
That’s the big risk with just adding a layer. Once you’ve got two sets of shingles, tracking down leaks gets way trickier. I’ve seen folks spend a fortune chasing water stains because you can’t see what’s happening underneath. Did you notice if your attic insulation or ventilation was up to snuff? Sometimes ice dams are more about airflow than the shingles themselves, but having two layers definitely doesn’t help.
I get why people go for the “just add a layer” option—it looks cheaper on paper and you avoid the mess for a while. But if you’re in a spot with heavy snow or big temperature swings, that shortcut can come back to bite you. I’ve torn off roofs where the bottom layer was rotted out and nobody knew until it was too late.
Curious if anyone’s had luck with synthetic underlayment when doing a full tear-off? I’ve heard it holds up better against leaks, but haven’t seen enough long-term results yet.
I’ve inspected a few roofs where folks went with synthetic underlayment after a full tear-off, and honestly, I haven’t seen any major issues yet—but most of those installs are less than five years old. One thing I did notice: the attic ventilation seemed to matter just as much as the underlayment. In one case, even with the fancy synthetic stuff, poor venting led to condensation and minor mold. Anyone else run into that? Sometimes I wonder if we focus too much on materials and not enough on airflow.