Metal roof vs shingles

"Metal roof" covers two products that behave nothing alike, and conflating them is why the comparison usually goes badly.

Standing seam is formed panels with concealed clips, the fasteners hidden inside the seam. The panels float, so they can expand and contract without tearing at the screws. $10 to $18 per square foot installed, 40 to 70 years, effectively no maintenance beyond keeping debris out of the valleys.

Exposed-fastener panel — corrugated or R-panel — is screwed through the face, with a rubber (EPDM) washer under each screw head. $6 to $12 installed. The panel steel will outlive you; the washers will not. They harden and shrink at 15 to 20 years and the roof needs every screw checked and many replaced. Do that and you get 40 years. Skip it and you get twenty and a lot of small leaks.

On the other side, architectural asphalt at $4.50 to $8.00 installed, 20 to 30 years, and three-tab at $3.50 to $5.50, 15 to 20 years.

I am comparing standing seam against architectural asphalt below, because those are the two products a homeowner is actually choosing between when the decision is being made seriously.

On a 24-square roof:

• Architectural asphalt: $13,000–$19,000
• Standing-seam metal: $26,000–$43,000

So metal is roughly double, sometimes closer to triple on a complicated roof, because a cut-up roof means more flashing and metal flashing is skilled sheet-metal work rather than a shingle cut with a hook blade.

Run it over fifty years, though, and the arithmetic reverses. One metal roof covers the period. Asphalt needs two roofs and possibly three, and the second one costs whatever roofing costs in 2050, not what it costs now. Even holding prices flat, two asphalt roofs at $16,000 beat one metal roof at $34,000 by very little, and the moment you assume any material inflation the metal wins.

The catch is that fifty-year arithmetic only pays out if you are there to collect it. The median American homeowner tenure is around a decade. If that is you, you are buying half a metal roof and leaving the rest to the next owner, who is not going to reimburse you for it at anything near cost. That is not an argument against metal — it is an argument about how long you're staying, which is why that is the first question and not the last.

The belief is that metal roofs are loud in rain. The usual rebuttal — "no, they're actually quieter!" — is overselling it.

Here is what is true. The noise people remember comes from metal over open purlins with nothing underneath: a barn, a carport, a porch. There is a panel, air, and then you. That is genuinely loud.

A house roof is not that assembly. There is a solid deck, underlayment (often a synthetic with an acoustic mat, or a full peel-and-stick), attic space, insulation and a ceiling. Measured, that assembly is within a few decibels of the same house with asphalt shingles — different in character, not meaningfully different in level. Some people notice a higher-pitched drumming in heavy rain and hail. Most do not notice anything.

So: not a reason to avoid metal on a house with an attic. Worth thinking about on a cathedral ceiling with no attic void, where the assembly is closer to the barn case — there, spend the money on a peel-and-stick underlayment over the whole deck and don't skip the insulation.

While we are dispatching myths: a metal roof does not attract lightning. Lightning strikes the tallest conductive path to ground in the area, which is your tree or your chimney. If a metal roof is struck it is a better conductor and less likely to ignite than asphalt.

Wind. Standing seam with concealed clips routinely carries ratings of 140 mph and above, and there are systems tested well past that. Architectural asphalt is 110 or 130 mph, and that rating assumes six nails placed correctly in the nailing strip, which is not what always happens on a Tuesday afternoon.

Fire. A Class A metal assembly over a fire-resistant underlayment is a real advantage in a wildland-urban interface. In parts of California and Colorado this is now the deciding factor and sometimes a requirement.

Snow. Snow slides off metal. That is mostly good — no ice dams building at the eaves — and partly a hazard, because a slab of snow releasing over a doorway or a driveway is dangerous. Snow guards are a $500 to $2,000 addition and are not optional over an entry.

Heat. A reflective metal roof with a PVDF finish and high solar reflectance cuts cooling load meaningfully in hot climates. Department of Energy work has put cool-roof cooling savings in the region of 7–15% of cooling cost, and it stacks with attic ventilation rather than replacing it.

Low slope. Standing seam works down to about 3/12, and mechanically seamed systems lower still. Asphalt starts getting nervous at 4/12 and is out at 2/12.

Insurance. In Florida, Texas, Colorado and Oklahoma several carriers now discount for an impact-rated Class 4 roof, and a properly specified metal roof qualifies. Discounts run 5–35% depending on carrier and state. Ask your carrier for the number in writing before you buy — the discount is real but it varies enough that you should not assume it.

You're moving inside ten years. Cost vs. Value data has never shown metal recovering its premium at resale. Buyers pay for a roof that isn't a problem, not for a roof that is exceptional.

The roof is cut-up. Six dormers, four valleys, three levels and two chimneys: every one of those is hand-formed metal flashing, and the labor premium on metal grows faster with complexity than the material premium does. A complicated roof can push metal to three times asphalt rather than two.

Repairs and future work. A shingle repair is one person, an hour, and a bundle. Repairing a standing-seam panel in the middle of a run often means unseaming a course, and finding someone competent to do it in ten years is harder in most markets. If you are likely to add solar, a skylight or a dormer later, factor in that penetrating metal is a specialist job — though standing seam has a real counter-argument here, since solar clamps to the seam without a single penetration, which is genuinely the best solar mounting substrate there is.

Appearance and neighbourhood. In some HOAs metal is not approved. In some streets it looks wrong. On a colonial or a traditional shingle-clad house, standing seam can read as agricultural, and that matters to how the house sells.

Budget reality. A $17,000 asphalt roof done properly this year — with tear-off, new flashing, corrected ventilation and ice-and-water membrane — beats a $34,000 metal roof you postpone for three years while the deck rots. The best roof is the one that goes on before the leak does.

Neither product wins here cleanly, so it needs its own paragraph.

Metal dents. Not structurally — a dented panel sheds water perfectly — but a hail event will cosmetically wreck a metal roof, and most insurers now write a cosmetic damage exclusion into metal roof coverage precisely because of it. You may find yourself with a functional roof that looks hammered and no payout. Standing seam in a thicker gauge (24 gauge rather than 26) and with a striated or ribbed profile resists this better than a flat pan, which shows every dent.

Asphalt does not dent, it bruises — the impact fractures the mat under the granules, and the failure shows up as accelerated wear over the next few years. Class 4 impact-rated shingles (SBS-modified, tested to UL 2218) exist for exactly this and cost $30 to $60 a square more. In hail alley they are the obvious buy, and they carry their own insurance discount.

In Denver, Dallas or Oklahoma City the sensible default is a Class 4 asphalt shingle, not metal, unless you have read your policy's cosmetic damage clause and are content with it.

Buy standing-seam metal if: you intend to keep the house fifteen years or more, the roof is simple enough that the labor premium stays near 2x, you live in a high-wind, wildfire or heavy-snow region, or you plan to put solar on it.

Buy architectural asphalt if: you are moving within a decade, the roof is cut-up, you are in hail country and have read the cosmetic exclusion, or the metal number means postponing the job.

Buy neither three-tab nor exposed-fastener metal unless the building is a rental, a barn or a shed. Both are the cheap version of a good idea, and both spend the difference back in maintenance and early replacement.

One more thing that outweighs the choice itself: whichever covering you pick, the flashing, the underlayment and the ventilation decide whether you get the top or the bottom of that product's lifespan. A well-detailed asphalt roof outlasts a badly-detailed metal one, and it costs half as much to have that argument.