Why does picking between layering new shingles or ripping everything off have to be so confusing?

I get where you’re coming from, but I’ve seen a few double-layer jobs hold up just fine, especially on houses with good ventilation and no signs of leaks or sagging. Not saying it’s always the way to go, but sometimes the old shingles are still solid and the extra layer actually helps with insulation a bit. Tearing everything off is cleaner, sure, but it’s not always in the budget for folks. Guess it depends on what you find once you start poking around.

I get why folks want to save money with a second layer, but I’ve seen too many issues pop up down the road - especially in humid spots or older homes. Sometimes you can’t spot rot or soft decking until you tear off the old stuff. Plus, warranties can get tricky with double layers. Not saying it never works, but I usually lean toward a full tear-off unless the first layer’s in really great shape. Just seems safer in the long run, even if it’s a bit more up front.

Sometimes you can’t spot rot or soft decking until you tear off the old stuff.

That’s exactly what happened at my uncle’s place - looked fine from the outside, but once we started pulling shingles, half the plywood was mush. Ever run into a situation where a second layer actually saved someone money in the long run? I haven’t seen it yet, but maybe I’m just unlucky.

once we started pulling shingles, half the plywood was mush

That’s rough. I’ve seen a few jobs where folks tried to save by going over the old layer, but every time there was hidden damage underneath, it ended up costing more when leaks showed up later. Maybe in super dry climates it could work, but around here (lots of rain), it seems like a gamble. Anyone ever found rot after just a few years because of a second layer?

Yeah, I’ve been there. Tried to save a few bucks by letting the roofer put new shingles over the old ones on my last place - regretted it about three years later when we started seeing soft spots and little leaks. Ended up having to rip everything off anyway, plus replace a bunch of plywood. Around here (Pacific Northwest), the rain just finds its way in if you don’t do it right. I get why folks want to avoid the mess and cost, but for me, it wasn’t worth the short-term savings.