Ice Dams
Does a metal roof prevent ice dams?
No. Heat escapes from the house into the roof assembly, melts snow from below, and the meltwater refreezes at the cold eave. Nothing in that sequence depends on the roofing material. What metal does is shed snow, which removes much of the fuel and genuinely reduces dams — a real benefit and not a fix. A badly air-sealed and ventilated house under a metal roof still gets them. Run the check.
So what does fix them?
Air-sealing the ceiling plane so heat stops entering the roof assembly, adequate insulation (especially at the eaves, where it is usually thin), and ventilation that keeps the deck close to outdoor temperature. In that order. If you are re-roofing anyway, the ventilation work belongs in the same job — the deck is open and it will never be cheaper.
Are heat cables a solution?
A symptom manager. They keep a channel open so water escapes, which prevents damage, and they do nothing about the cause while adding running cost every winter. Reasonable as a stopgap or where the real fix is genuinely impractical. Not a repair.
Are icicles the same as ice dams?
Not necessarily. Icicles can form from ordinary solar melt on a mild sunny day with no heat loss at all. A dam is a ridge of ice sitting on the roof surface at the eave — and the giveaway is ice building during a cold spell when the air never rises above freezing.
The Numbers
What does a metal roof cost here?
Standing seam $12–$20 per square foot installed: Galvalume $12–$16, aluminium $14–$20, copper $25–$40. Steel metal shingles $8–$14. Asphalt $6–$10. A typical 1,600 sq ft roof in standing seam is roughly $19,200–$32,000. Estimate yours.
Why do quotes vary so much for the same size house?
Because roof area is not footprint, and complexity matters more than either. Multiply footprint by 1.06 shallow, 1.25 moderate, 1.45 steep to get actual area — then valleys, dormers, hips, chimneys and the junctions of connected ells do the rest. Two roofs of identical square footage can differ by half again.
How long does it last?
Standing seam 40–60 years as published for NH, with 40–70 cited for correctly installed steel or aluminium in freeze-thaw climates. Exposed-fastener panel 25–40, because the fasteners and washers are the wear item. Asphalt 18–25 here, up to 30 on premium architectural well ventilated.
Is it worth it?
Over a long enough horizon, usually — fifty years is one metal roof against two or three asphalt ones plus tear-offs and disposal. Up front it costs roughly double. If you are selling within a few years, asphalt is the more rational purchase and we will say so. Run the comparison on your roof.
Things People Believe
Is it noisy in the rain?
Not over a solid deck with underlayment and an insulated assembly beneath it. The noise people remember is from panel screwed to open purlins over an uninsulated barn — nothing between the metal and the space below. A house roof is a different construction entirely.
Does it attract lightning?
No. Height and location determine strike probability, not material. A struck metal roof is non-combustible and conducts the charge, which is arguably the safer outcome. This is the most persistent myth in the trade and there is nothing behind it.
Is it too heavy?
The reverse. Metal is lighter than asphalt — standing seam steel weighs a fraction of a shingle roof per square. The framing question that genuinely comes up is on old barns and connected ells that have been modified, and that gets inspected.
Will it dent in hail?
Heavier gauge resists better, and standing seam over a solid deck is considerably more resistant than panel over open framing. Severe hail can mark any roof. Hail is also a less frequent event here than in much of the country, and freeze-thaw is by far the bigger consideration.
Does it make the house hotter?
Generally cooler. Metal reflects rather than absorbs, and a light or reflective finish measurably reduces solar gain against dark asphalt. In this climate that is a minor benefit, but it is not a cost.
Will it rust?
Galvalume and aluminium are coated or inherently corrosion-resistant, and modern finish systems are good. Where you do want to think about it is cut edges, fastener choice, and dissimilar metals in contact — those are installation details rather than material problems. Near salt or heavy road-salt spray, aluminium is worth the premium.
Doing the Job
Do I need snow guards?
Wherever a slide would land somewhere that matters — an entrance, a walkway, a deck, a propane tank, an outdoor unit, a neighbour's drive. Metal releases snow suddenly and in quantity. $1–$3 per square foot of protected area. On an open elevation with nothing beneath the eave, you may genuinely not need them.
Can solar go on it?
Yes, and standing seam is the best roof there is for it — clamps grip the seams with no penetrations at all. If solar is anywhere in your plans, say so before the roof is specified so the seam spacing can be planned around it.
Can metal go over existing shingles?
Sometimes, rarely our recommendation. It hides the deck, which is the most useful thing a re-roof reveals, and complicates the eave and ventilation detailing that matters most here. Check local rules on layers too.
What maintenance does it need?
Little, though not none. Keep valleys and gutters clear, check flashing and sealant at penetrations every few years, and look at the snow retention after a hard winter. What fails on a metal roof is almost always the details rather than the panels.
What is oil-canning?
The slight waviness visible in flat metal panels at certain angles and light. An aesthetic characteristic of the material, not a defect, and it does not affect performance. Heavier gauge, narrower pans and striations in the pan all reduce it. Ask to see a panel in daylight.
How long does installation take?
A straightforward house roof is a few days to a week depending on size, complexity and weather. Complex roofs with a lot of flashing take longer, and site-forming panels adds setup. Weather governs more than anything — nobody should be handling metal panels in high wind.