In most cases, yes. Installing metal over existing asphalt shingles — a recover — is an accepted method, provided the deck underneath is sound and your local code permits it.
The common objection is weight, and it’s largely misplaced. Metal roofing is light relative to asphalt, so a single layer of metal over one layer of shingles is rarely a structural problem. The real questions are about what you can’t see and what you’re giving up.
What a recover involves
A metal recover, deck outward. The old shingles stay and become part of the assembly.
The old shingles stay. A slip sheet or underlayment goes over them so the metal isn’t in direct contact with asphalt, and depending on the system, furring strips create a flat plane and an air gap over an uneven surface.
That air gap is a genuine benefit — it gives the assembly some thermal separation and a drainage path — but it also means the finished roof sits slightly higher, which affects flashing details at walls, chimneys and edges.
What it saves
Tear-off and disposal. This is the whole economic case. Stripping a roof is labour plus dumpster plus landfill, and skipping it removes a meaningful line from the quote.
Time. Fewer days on site, and no window where the deck is exposed to weather.
Waste. The old shingles don’t go to landfill — at least not yet.
Roofing installation labour runs $150 to $500 per square (EstimationPro.AI construction cost dataset, 2026), and tear-off is a real share of the crew time on a re-roof. The saving is not trivial.
What it costs you
You can’t inspect the deck. This is the significant one. The condition of the sheathing is the single biggest unknown on any roofing job, and a recover is a decision to not find out. If there is soft decking, rot around a penetration, or damage from a leak that was never traced, it stays there — now under two roofs.
Later work is harder. When the metal eventually comes off, two layers come off, and the disposal you deferred arrives with interest.
Some codes limit layers. Many jurisdictions cap total roofing layers, and some require tear-off for a material change. This is a local question with a local answer.
Warranty terms vary. Some manufacturers’ terms differ for recover installations. Worth reading before, not after.
When a recover makes sense
- The existing shingles are a single layer and lying reasonably flat
- The deck has no history of leaks and no soft spots underfoot
- You have no interior signs — no staining, no attic moisture
- Code allows it, and the installer confirms it in writing
- You want the metal roof primarily for its performance, not to reset the assembly
When to tear off instead
- Any evidence the deck has been wet: interior stains, attic damp, a leak that was patched rather than traced
- Two or more existing layers
- Shingles that are curled, buckled or badly uneven, which telegraph through the metal
- You’re already doing structural work, flashing replacement or a ventilation upgrade
- The roof is old enough that you’d want the deck inspected regardless
The deciding question isn’t really cost. It’s whether you have any reason to doubt what’s under the shingles. If you do, the saving disappears the first time a leak turns into deck replacement through two roofs.
Asking for the quote
Get both priced. A competent roofer will quote a recover and a tear-off side by side and tell you which they’d do on your roof, and the reasoning matters more than the difference.
Ask specifically: how the deck condition was assessed without removing shingles, what happens if soft decking is found mid-job, whether the metal system is fastened through to the deck or to furring, and how the flashing at walls and chimneys accounts for the added height.
For what metal costs against asphalt by home size and market, see the roofing cost guide. For the per-square breakdown, see what roofers are actually quoting.
