Do I need to remove my shingles before installing a metal roof?

Not always, but sometimes yes. If you already have two or more layers of shingles, if the deck underneath is soft or rotted, or if your municipality's code requires tear-off for a re-roof, then removal isn't optional. We won't know which situation you're in until we've inspected the actual deck.

Does metal roof underlayment work differently over an existing shingle layer?

Yes — the underlayment and any furring-strip or batten system between the old shingles and the new metal panels is what manages ventilation and prevents the panels from telegraphing the old roof's texture and unevenness. Getting that layer right is one of the parts of an over-frame job that separates a roof that lies flat and performs from one that doesn't.

Does installing a metal roof over shingles void the manufacturer warranty?

It depends on the manufacturer and the specific system. Some panel manufacturers explicitly allow and detail over-frame installation; others require a bare deck for the warranty to apply in full. This is exactly the kind of detail that gets missed on a phone estimate and has to be confirmed against the actual product being installed before you sign anything.

What about local building codes — does every city in Baldwin and Mobile County allow it?

Codes vary by municipality on this coast, and we don't publish a blanket answer because it would be wrong somewhere. We confirm the applicable code for your specific address before quoting the job, so what you get is a real answer for your house, not a guess that might not hold up at permit review.

Metal Roofing · Baldwin & Mobile County, AL

Can you put a metal roof over shingles?

Often, yes — one layer of metal installed over one existing layer of shingles, if the deck underneath is sound and local code allows it. That's the short version. The real answer for your specific roof depends on what an inspection finds, which is the honest part most pages selling this job skip.

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The conditional part

When it works, and when it doesn't

"Often yes" isn't the same as "always yes." Here's what has to be true either way.

Generally works when

One layer of shingles already on the roof, not two or more
The deck underneath is sound — no rot, no soft spots, no delamination
The roof planes are reasonably flat, without a lot of built-up unevenness from age or prior repairs
Local code in your municipality allows an over-frame installation on your property
The manufacturer's installation and warranty terms permit installing over an existing layer

Generally doesn't when

Two or more layers of shingles already on the roof — most codes cap it at one, and stacking a third adds weight the framing wasn't designed for
Soft, spongy, or delaminated decking anywhere the inspector checks — that has to be found and replaced, which means opening the roof anyway
Uneven or wavy roof planes from age, prior patch repairs, or old storm damage — metal panels telegraph an uneven substrate visibly, and standing-seam is especially unforgiving of it
A municipality that doesn't allow over-frame installations, or a permit process that requires tear-off
A manufacturer warranty that's void or reduced when installed over an existing layer rather than a bare deck

What's different about the install

Venting and underlayment, over an existing layer

Metal over shingles isn't just laying panels on top of what's there. A furring-strip or batten system typically goes down first, spaced to let air move underneath the metal — that airspace is what keeps the panels from telegraphing the texture and unevenness of the old shingle layer, and it matters more on an over-frame job than on a bare-deck one.

The underlayment spec sits on top of that framework, and it has to be rated for the panel system going over it. Ventilation at the ridge and eaves also has to keep working the same way it did before — an over-frame job that blocks existing venting is a moisture problem waiting to happen, not a shortcut.

Coastal caveat: the wind spec still applies

An over-frame job doesn't lower the bar on uplift rating or fastener corrosion class. The panel system still has to be rated and detailed for this coast's wind field the same way it would on a bare deck — the layer underneath changes the installation method, not the performance requirement.

See our metal roof cost guide for how the coastal fastener spec factors into a quote.

Why we won't answer this by phone

An inspection is the real answer, not a rule of thumb

Every condition on the "when it works" list above is something we have to see, not something you can describe accurately over the phone — layer count, deck condition, roof-plane flatness, and what your specific municipality's code requires. A roofer who tells you "yes" before walking your roof is guessing, and a roofer who tells you "no" before walking it might be talking you into a bigger job than you need.

What we check: shingle layer count, deck soundness at multiple points, roof-plane flatness, existing ventilation path, and the code requirement for your address. You get a straight answer — over-frame or tear-off — before we quote anything.

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What Liberty checks

How many layers are already on the roof
Deck condition at multiple points, not just a visual pass
How flat and even the roof planes actually are
Whether existing ventilation keeps working under the new plan
What your municipality's code actually requires

Sometimes the honest answer is "tear it off"

We'd rather tell you your deck needs a tear-off than install over a problem and have it show up in two years. If your inspection turns up rot, two-plus layers already on the roof, or a code requirement that rules out over-frame, that's what we'll tell you — and we'll explain why before you decide anything.

Common questions

Metal roof over shingles FAQ

Can you put a metal roof over shingles?: Often, yes. Metal roofing can generally be installed over one existing layer of shingles, provided the deck underneath is sound, the roof planes are reasonably flat, local code in your municipality allows it, and the metal panel manufacturer's warranty terms permit an over-frame installation. "Generally" is doing real work in that sentence — the honest answer only comes from an inspection of your specific roof, not a blanket rule.
Do I need to remove my shingles before installing a metal roof?: Not always, but sometimes yes. If you already have two or more layers of shingles, if the deck underneath is soft or rotted, or if your municipality's code requires tear-off for a re-roof, then removal isn't optional. We won't know which situation you're in until we've inspected the actual deck.
Does metal roof underlayment work differently over an existing shingle layer?: Yes — the underlayment and any furring-strip or batten system between the old shingles and the new metal panels is what manages ventilation and prevents the panels from telegraphing the old roof's texture and unevenness. Getting that layer right is one of the parts of an over-frame job that separates a roof that lies flat and performs from one that doesn't.
Does installing a metal roof over shingles void the manufacturer warranty?: It depends on the manufacturer and the specific system. Some panel manufacturers explicitly allow and detail over-frame installation; others require a bare deck for the warranty to apply in full. This is exactly the kind of detail that gets missed on a phone estimate and has to be confirmed against the actual product being installed before you sign anything.
What about local building codes — does every city in Baldwin and Mobile County allow it?: Codes vary by municipality on this coast, and we don't publish a blanket answer because it would be wrong somewhere. We confirm the applicable code for your specific address before quoting the job, so what you get is a real answer for your house, not a guess that might not hold up at permit review.
Does the coastal wind spec still apply if metal goes over the old shingles?: Yes. An over-frame installation doesn't lower the bar on uplift rating or fastener corrosion class — the panel system still has to be rated and detailed for this coast's wind field the same as it would on a bare-deck job. The layer underneath changes the installation method, not the performance requirement.

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