That’s a good point about the hidden rot—seen that myself more times than I’d like.
That’s exactly why I lean toward full tear-offs, even if it’s a pain up front.“when we tore off two layers, there was a ton of rotten decking underneath, totally hidden by the shingles”
From my end, there’s also the environmental angle. When you layer new shingles over old, you’re not just risking unseen damage—you’re also missing the chance to upgrade insulation or install a cool roof membrane. I did a job last fall where we pulled everything off and swapped in recycled-content underlayment. It made a noticeable difference in attic temps (and the homeowner’s bills). You can’t really do that with a layover.
I’m curious—has anyone tried integrating solar shingles or green roof sections during a full replacement? Seems like if you’re already down to the deck, it’s the ideal time to rethink what goes back up... or am I overcomplicating things for most folks?