Weighing the pros and cons: full roof removal vs. just adding a new layer

One thing I’d throw out there - did you check for any soft spots or hidden damage before adding that second layer? I’ve seen a few jobs where the decking looked fine from the attic, but once we pulled the old shingles, there was rot around vents or valleys that nobody caught until tear-off. Covering it up with another layer can mask those issues for a while, but they’ll come back to bite you down the road.

Also, about the weight - yeah, southern Indiana doesn’t get crazy snow loads, but even without snow, two layers can stress older rafters over time. Not saying it’s always a dealbreaker, but I’ve run into sagging on houses from the 60s and 70s after double-layering.

I get the cost savings though. Sometimes budgets just don’t stretch for a full tear-off. Just curious - did your roofer mention anything about warranty differences? Most shingle manufacturers won’t honor their full warranty if you go over an existing layer. Not everyone cares about that, but it’s worth knowing.

Just my two cents... sometimes what saves money now can cost more later if there’s hidden damage or warranty headaches.

Not to stir the pot, but I’ve actually seen a few cases where going over an existing layer made sense, especially on houses with solid decking and no history of leaks. I get the concerns about hidden rot - definitely a risk - but sometimes you can spot trouble areas from the attic or by checking for spongy spots on the roof itself. It’s not foolproof, but it’s better than nothing if a full tear-off just isn’t in the cards budget-wise.

About the weight, I’m a bit less worried unless we’re talking about really old framing or already sagging rafters. Most modern homes can handle a second layer, at least around here, but I wouldn’t push it past that. Two layers is my hard limit.

The warranty thing is a pain, though. I’ve had homeowners surprised when they find out their “30-year” shingle is only covered for 10 or 15 because it’s a layover. Not everyone reads the fine print, and some roofers gloss over it. I always tell folks to double-check what they’re actually getting.

At the end of the day, it’s a trade-off. Sometimes you just have to pick your battles and hope you’re not covering up a bigger problem.

That’s a good point about checking from the attic or feeling for soft spots - sometimes you can catch issues before they get buried. I’ve noticed, though, that even with a solid deck and no leaks, there’s always that nagging worry about what you can’t see. I guess it comes down to how much risk you’re willing to take, especially if the budget’s tight.

I’m with you on the weight thing. Around here (Midwest), most homes built after the 70s seem to handle a second layer fine, but I’ve seen some older bungalows where even one layer looks like it’s pushing it. Ever seen rafters bowing just from age? Makes me nervous to add anything extra. I wonder if anyone’s ever actually had a roof collapse from two layers, or if that’s more of a theoretical risk.

The warranty issue is a real headache. I’ve had friends who thought they were set for decades, only to find out the fine print cut their coverage in half because of a layover. It feels like something contractors should be upfront about, but I get how it gets missed in all the paperwork and estimates. Do you think most homeowners actually read those warranty details? I know my parents didn’t when they replaced their roof last year - they just trusted the contractor.

One thing I’m still not sure about is how much harder it is to spot leaks or rot once there are two layers up there. Does anyone have tips for checking that stuff without tearing everything off? I’ve heard about using infrared cameras, but not sure how practical that is for most folks.

It really does feel like a balancing act - cost, risk, and what you can live with. Sometimes you just gotta make the best call for your situation and hope you’re not setting yourself up for a bigger headache down the road.

I’ve always wondered how many people actually read the full warranty, too - feels like it’s written in a secret language. As for spotting rot with two layers, I’ve heard moisture meters can help, but honestly, nothing beats pulling stuff up and seeing for yourself. The weight thing freaks me out a bit on old houses... I’ve seen some gnarly sagging in my neighborhood after heavy winters. Anyone else notice that shingles double up seem to trap more heat, too? Not exactly eco-friendly.

The weight thing freaks me out a bit on old houses... I’ve seen some gnarly sagging in my neighborhood after heavy winters.

Yeah, the weight is a real concern, especially with older homes. I’ve been on a few jobs where we started pulling up the first layer and found the decking was already borderline - like, you could feel it flex under your boots. Adding another layer would’ve just made it worse. Sometimes folks think it’s just “one more layer,” but those shingles are heavy, especially after they soak up some rain or snow.

About the heat trapping, you’re not wrong. Double layers definitely seem to hold more heat. I’ve noticed in the summer, the attic gets way toastier when there’s two layers up there. Makes the AC work harder, and I’m guessing that’s not great for energy bills or the planet. Plus, if you ever need to do repairs, cutting through two layers is a pain. Nails don’t always grab right either.

I get why people want to save money and time by just going over the old shingles, but honestly, every time I’ve seen someone do that, it’s just kicking the can down the road. You miss out on seeing what’s really going on underneath - rot, bad flashing, whatever. Moisture meters help, but like you said, nothing beats actually looking.

Warranties are a whole other headache. Half the time, if you read the fine print (which is brutal), they don’t even cover you if you’ve got two layers or if the install isn’t perfect. I tried reading one last week and gave up halfway through... felt like I needed a law degree.

If it’s an old house and you’re worried about sagging or rot, I’d lean toward full tear-off. Costs more upfront, but at least you know what you’re working with. Plus, you can upgrade the underlayment or add better ventilation while you’re at it. Just my two cents from being up there and seeing what happens when shortcuts get taken.