Why you should tear off your old roof, not roof over it

When it's time for a new roof, you'll sometimes hear about "roofing over" — laying a fresh layer of shingles right on top of the old one instead of ripping it off first. It sounds like a smart way to save a little money: no tear-off labor, no disposal fee, less mess.

We almost never recommend it. On a Vermont home, a full tear-off is worth every dollar, and here's the plain-English reasoning behind that.

1. It voids your shingle warranty

This is the one most homeowners never hear until it's too late. Most major shingle manufacturers will only honor their warranty when their product is installed over a clean, bare roof deck — not on top of old shingles.

Roof over the existing layer and you've quietly cancelled the very warranty you're paying a premium for. If something goes wrong down the road, you're on your own. A brand-new roof with no warranty behind it isn't a bargain.

2. It piles weight onto your structure

Shingles are heavy. A single layer of asphalt shingles runs roughly two to three-plus pounds per square foot — across a whole roof, that's thousands of pounds. Add a second layer and you've doubled it.

In Vermont, that extra dead weight sits on the structure all winter, underneath a snow load that can already stress the framing. Rafters and decking are sized for one roof, not two. Piling a second layer on top is exactly the wrong direction in a climate that already tests your roof every February.

3. The new layer is only as good as the dead one under it

Here's the part that gets glossed over: your new shingles have to lie flat and seal properly to do their job. Lay them over an old, worn-out roof and they follow every ripple, curl, and high spot underneath.

The old layer is at the end of its life — that's why you're replacing it. It's brittle, uneven, and often cupped. Bond a fresh roof to that and you get:

• Shingles that don't lie flat, so they're more prone to wind uplift and premature failure.
• Trapped heat, because two layers hold more of it and can cook the new shingles from below.
• A lumpy, second-rate look that telegraphs "roofed over" from the street.

You're spending real money on new material and then handicapping it from day one. Why save a layer that's already dead?

4. You can only fix rotten decking if you tear off

This is the big one, and it's the reason we insist on it. Until the old shingles come off, nobody can see the wood underneath. Roof over the top and whatever's under there — soft spots, water-stained sheathing, rot around a chimney or a leaky valley — stays hidden and keeps rotting.

A tear-off turns the roof into an open book. We walk the bare deck, find the bad plywood, and replace it before the new roof goes on. That's also when we can lay proper ice-and-water shield along the eaves — impossible to do right when you're covering an existing layer. In a place that gets ice dams, that membrane is what keeps backed-up meltwater out of your ceilings.

Roof over the problem and you've sealed it in for another 20 years. Tear off, and you fix it once.

The honest math

Yes, a tear-off costs more up front — you're paying for the labor to strip the old roof and the fee to haul it away. But you're getting a roof that:

• Keeps its full manufacturer warranty.
• Doesn't overload your framing.
• Lies flat and lasts its full rated life.
• Sits on sound, inspected decking instead of hiding rot.

That's not an upsell — it's the difference between a roof that lasts and one that just looks new for a couple of seasons.

If you're weighing a re-roof and want a straight answer on what a proper tear-off would cost for your house, send us a few photos and details and we'll get you a clear, itemized price — remotely, with no home visit to get your quote. Like the number? We come out and meet you in person before you commit.