Are metal roofs good in storms? Yes: a properly installed metal roof sheds rain quickly, resists wind uplift when it matches its tested assembly, does not attract lightning and does not burn. No roof is failure-proof, though. When a metal roof lets a storm in, the cause is almost always a detail (flashing, a screw, a pipe boot, a lifted trim piece or a clogged valley) rather than the panels. Below are the questions homeowners ask most, with straight answers. If a storm has already damaged your roof, call NEMA Roofing at 866-631-3366.
Does a metal roof leak in heavy rain?
The panels themselves do not soak up water or let it through. Leaks on metal roofs start where the roof is cut, joined or meets something else:
- Pipe and vent boots. Rubber boots age in the sun. The Department of Defense roofing criteria (UFC 3-110-03) call for EPDM boots with an aluminum compression ring, placed in the middle of a panel rather than across a seam.
- Sidewalls and chimneys. Flashing that relies on exposed sealant alone fails as the sealant ages.
- Exposed screws. On screw-down panels each washer is a seal; a loose or over-driven screw lets water in.
- Too little slope. Lapped panels need more slope than standing seam; laid too flat, wind-driven water backs up through the laps.
- Clogged valleys and gutters. Leaves dam the water until it runs sideways under the trim.
Most of these are maintenance items, which is why a yearly look at the details matters more than the panel brand.
Is a metal roof loud when it rains?
It depends on what is under the metal. The drumming people remember usually comes from panels fastened straight to open framing, as on barns and carports, with nothing under them. On a house, the California Residential Code has metal panels fastened to wood structural panels or lumber sheathing (unless the panel is designed for spaced supports), with underlayment between the deck and the metal, and there is usually an insulated attic below that. Each layer absorbs sound. If quiet matters to you, ask the roofer to confirm a solid deck, the underlayment type and the attic insulation level, and consider adding insulation during the reroof.
Do metal roofs attract lightning?
No. The National Weather Service lists this as a myth: height, a pointed shape and isolation decide where lightning strikes, and the presence of metal makes no difference. Trees and mountains, with little or no metal in them, are struck many times a year because they are tall and isolated. If a metal roof is struck, the metal does not burn. Where a lightning protection system is wanted, the military roofing criteria call for aluminum components on metal roofs, attached without holes through the panels at valleys and eaves. Indoors, the Weather Service’s advice holds for every roof type: stay off corded phones and away from plumbing and electrical appliances during a thunderstorm.
How does a metal roof handle hail and falling branches?
Impact resistance for steep-slope roofing is tested under UL 2218, which drops steel balls on the most vulnerable spots of a sample (edges, corners, joints and unsupported areas). The standard itself says there is no established direct correlation between steel-ball results and real hail, and it does not measure the effects of aging. So an impact rating is a useful comparison between products, not a guarantee. Low-slope roofs have their own test, UL 2218A.
After a hailstorm or a falling branch, the question is whether the finish is broken:
- A shallow dent with the paint intact is usually cosmetic.
- A scratch, crack or puncture through the paint exposes the metallic coating and needs repair before it corrodes.
- A dent at a seam, a clip or a screw can loosen the connection and should be checked from the roof.
What fails first on a metal roof in a storm?
| Part | What goes wrong | How it is prevented |
|---|---|---|
| Rake and eave trim | Wind gets under a loose edge and peels it back | Heavier-gauge edge metal, fastened to the tested pattern |
| Ridge and hip caps | Suction lifts caps; wind-driven rain enters under them | Closures under the cap and fastening at the specified spacing |
| Exposed screws | Washers dry out; screws back out as panels expand and contract | Concealed-clip panels, or scheduled screw checks on screw-down roofs |
| Pipe boots and curbs | Cracked rubber; curbs that pin the panel and tear the seal | EPDM boots, curbs detailed so the panel can move |
| Valleys and gutters | Leaves dam water that overflows under trim | Cleaning before the rainy season; gutter guards |
The engineering behind wind ratings and panel movement is in metal roof wind resistance, heat and age, and the way each kind of severe weather in Southern California tests a roof is in metal roofing for extreme weather.
What should you do after a storm damages the roof?
- Stay off the roof. Wet metal is slippery, and damaged panels can have sharp edges.
- Document it. The California Department of Insurance advises taking pictures and keeping records of all clean-up and repair costs, and reporting the damage to your insurer.
- Read your policy. According to the Department, flood, mudslide and debris-flow losses are usually excluded from homeowners coverage; storm water that wind drives in through the roof may be covered, and fallen-tree damage generally is.
- Stop the water inside. Move belongings and catch drips; note where stains appear, since they point to the leaking detail above.
- Get the roof inspected. A roof inspection finds the failed detail and documents it for the claim.
Storm-ready metal roofs from NEMA Roofing
NEMA Roofing has five locations (Oxnard, Santa Barbara, Downey, Tarzana and Woodland Hills) and serves every county from Santa Barbara and Ventura to Los Angeles, Riverside and San Bernardino. Wherever you live in the Ventura County service area or the other four counties, a NEMA team works near your town. See the systems we install on the metal roofing page, or call 866-631-3366 to have a metal roof checked or planned before the next storm season.
