What is a metal roof?
Updated August 2026
A metal roof is a roof clad in interlocking steel or aluminum panels instead of shingles, shedding water and snow fast and carrying a Class A fire rating. Two families cover nearly every house. Standing seam hides its fasteners under raised vertical seams, lets panels expand and contract freely, and lasts 40–70 years. Exposed-fastener panels, the corrugated or R-panel look, screw straight through the face with rubber-gasketed screws, cost roughly half as much, and trade that savings for gaskets you have to service.
Where it is
Identify what you have from the driveway. Standing seam shows 1–2 inch raised ribs every 12–18 inches with no screw heads anywhere in the field. Exposed-fastener panels show neat rows of screw heads every 12–24 inches. Stone-coated steel and metal shingles imitate tile or shake and read as texture rather than panels. Two specs then decide how the roof ages. Gauge: 24-gauge steel is the residential standard for standing seam, while 26–29 gauge is common on budget panels and dents more easily. Finish: a PVDF (Kynar) coating carries 30–40 year color warranties, while cheaper polyester chalks and fades in 10–15 years.
What it does
Metal earns its price on shedding and survival. Panels drop snow before it loads the structure, meet Class A fire ratings, carry wind ratings of 110 to 140 mph, and in a light cool-roof color measurably lower attic temperature. What fails is never the metal; it is the details around it. Neoprene washers on exposed-fastener screws harden and shrink in 10–15 years, the screws back out, and rust rings bloom around the heads. Sealant at ridges, valleys, and pipe boots cracks on a similar clock. Foot traffic dents thin panels, and dissimilar metals touching, such as copper flashing on steel, corrode at the joint. Oil-canning, the gentle waviness across flat pans, is cosmetic rather than a defect. The first symptom most owners notice is a screw lying in the gutter.
Maintenance
Walk the perimeter with binoculars twice a year and again after hail or high wind, using the metal roof maintenance checklist; how long a metal roof lasts sets expectations by panel type. Keep valleys clear of pine needles, which hold moisture against the seams, and touch up any scratch that reaches bare metal within the season. The big scheduled item belongs to exposed-fastener roofs: a full re-screw every 10–15 years with larger-diameter fasteners and fresh washers, at $0.75–2.00 per screw or $1,500–4,000 for an average roof. Standing seam has no equivalent chore. When damage shows up, repair or replace sets the threshold and replacement timing covers the horizon.
What it costs to replace
A replacement metal roof runs $10,000–30,000 installed on an average home, roughly $8–16 per square foot for standing seam and $4–9 for exposed-fastener panels.
OnOtto's photo scan identifies parts like this in your home and builds the maintenance schedule for you. See how the scan works.
Frequently asked questions
Is a metal roof loud in the rain?
Not on a house. The drumming reputation comes from barns, where panels sit on open purlins with nothing but air behind them. A residential metal roof goes over solid decking, synthetic underlayment, an attic, and insulation, and measured sound levels land close to asphalt shingles. Over a cathedral ceiling with no attic buffer, a layer of rigid foam or peel-and-stick underlayment closes the small gap that remains.
Does a metal roof attract lightning or block cell service?
Neither. Metal does not attract strikes, and because it is non-combustible and conductive it disperses one better than wood or asphalt does. Cell and wifi signals already pass through walls rather than the roof in most homes, though a satellite dish or an attic-mounted antenna may need repositioning. The insurance angle is more interesting: many carriers in hail states discount impact-resistant roofs rated UL 2218 Class 4, so ask before you sign a contract.
Can metal panels go over existing shingles?
Often yes, and it saves $1,000–3,000 in tear-off and disposal. The usual conditions: one existing layer, sound decking, code approval, and furring strips or a slip sheet so panels do not telegraph shingle lines or abrade underneath. The tradeoff is that nobody inspects the deck for rot before covering it, and a hidden soft spot becomes an expensive surprise. On a roof past 20 years, tear off.
Is a metal roof worth twice the price of shingles?
Divide by years. A $20,000 standing seam roof over 50 years is about $400 a year. A $9,000 architectural shingle roof over 22 years is about $409 a year, plus a second tear-off you have to live through. Cost per year is close to a wash, so decide on the other factors: how long you plan to stay, wildfire or hail exposure, snow load, and whether you would rather do this project once instead of twice.