I’ve run into that same “hidden rot” problem more than once. Last year, we had a duplex where the owner insisted on just adding a layer to save money. Looked fine from the outside, but six months later, we found soft spots near the chimney—turned out water had been sneaking in for years. Ended up costing way more to fix the decking and interior damage than if we’d just done a full tear-off.
That said, I get why some folks want to avoid the landfill issue. It’s not nothing, especially with how much waste a tear-off creates. But honestly, I’d rather deal with that upfront than risk mold or structural headaches down the road.
Curious if anyone’s had luck with those newer synthetic underlayments? I’ve heard they can help with moisture issues even if you do add a second layer, but haven’t tried them myself yet. Wondering if that’s actually a decent compromise or just marketing hype...
Tried the synthetic underlayment on my own place last fall—figured it couldn’t hurt since I’m in the “rain every other day” part of the country. It’s definitely tougher than old-school felt, and it handled a surprise week of storms before the shingles went on. But honestly, if there’s already rot or sketchy decking underneath, no fancy underlayment’s gonna save you. It’s like putting a band-aid on a leaky canoe. Still, I’d pick synthetic over felt for a second layer, but only if the base is solid.
Title: Weighing the pros and cons: full roof removal vs. just adding a new layer
You nailed it with the underlayment comparison—synthetic’s definitely tougher, especially if you’re dealing with unpredictable weather. I’ve seen it hold up through some nasty storms when jobs got delayed, so I trust it more than felt for temporary exposure.
But yeah, if your decking’s already soft or showing signs of rot, no underlayment is gonna fix that. I always tell folks: before you even think about a second layer, walk the roof (carefully) and check for spongy spots or visible sagging. If you find any, it’s time to strip everything down and replace the bad wood. Otherwise, you’re just hiding a problem that’ll bite you later.
One thing I’d add—if your area gets heavy snow or ice, synthetic underlayment can help with ice dam protection, but only if it’s installed right and the base is solid. And keep in mind, adding a second layer can void some shingle warranties and make future repairs trickier. Sometimes it’s tempting to save on labor by skipping the tear-off, but long-term, a clean deck is worth it.
I’ve managed a few buildings where we debated this exact thing—tear-off vs. just layering new shingles. Honestly, I lean toward full removal, especially if the roof’s pushing 20 years or you’ve had leaks. It’s a pain upfront, but you get to see what’s really going on underneath. Had a place where we thought it was just old shingles, but once we pulled them up, half the decking was basically mulch. Would’ve never caught that with a second layer.
That said, I get why folks go for the overlay if the budget’s tight and the decking’s solid. It’s faster, less mess, and you’re not left with a yard full of dumpster bins. But like you said, warranties can get tricky, and I’ve noticed repairs down the line are more of a headache—especially tracking leaks.
One thing I’m still not clear on: does adding a second layer really make the roof hotter in summer? I’ve heard mixed things. Anyone actually notice a difference?
just layering new shingles.
I’ve wondered about the heat thing too. Last summer, we did an overlay on my uncle’s place (asphalt shingles, midwest, not a ton of shade). He swears it felt hotter upstairs after, but honestly, I couldn’t tell much difference myself. Maybe it depends on attic ventilation? I do think you’re right about repairs being trickier—tracking leaks through two layers is a headache. Still, if the decking’s solid and you’re pinched for cash, I get why people go for it. Just wish there was a clear answer on the heat buildup.