A metal roof needs far less upkeep than shingles, but no maintenance is a sales line, not a fact. Good metal roof maintenance is a yearly look from the ground, clean gutters and valleys, and a professional check of the sealants, fasteners and flashings every few years. Never walk on your roof to do any of this; hire someone who does it for a living.
What actually wears out on a metal roof
The metal itself is the last thing to fail. Painted steel and aluminum roofs commonly last 40 to 70 years, and copper and zinc go past 100. What ages first are the parts that are not metal or not painted at the factory. Sealants at flashings, end laps and penetrations have a service life measured in years, not decades. The rubber washers under exposed screws dry out and shrink. Pipe boots crack in the sun. Debris piles up in valleys and behind chimneys and holds water against the panels. Scratches that reach bare steel can start to rust at the edge. And metal that touches the wrong material, such as copper, lead or treated lumber, corrodes where they meet. Maintenance is simply catching those small things before they become a leak.
Your yearly routine, from the ground
Pick a weekend each year, and repeat after any storm with high wind or hail. Everything on this list can be done from the yard, a window or the attic.
- Walk the perimeter and look up at every slope. You are looking for lifted or shifted panels, loose or missing trim, a ridge cap that has moved, bent gutters, and snow guards or other hardware that look out of line.
- Use binoculars to check exposed screw lines for heads that stand up or are missing, and valleys and the uphill side of chimneys for leaves and needles.
- Look at the underside of the eaves and the fascia for staining or peeling paint, which can point to water getting behind the gutter.
- Check ceilings and the attic after a hard rain for stains, damp insulation or daylight around penetrations.
- Have the gutters and downspouts cleaned in late fall and again in spring if you have trees, and ask the gutter crew to clear anything resting in the valleys while they are there.
- Keep branches cut back so they cannot rub the roof in wind or drop debris on it.
| Task | How often | Who does it | Why it matters |
|---|---|---|---|
| Visual check from the ground | Yearly and after storms | You | Catches shifted panels, loose trim and debris early |
| Gutter and valley cleaning | Once or twice a year | Gutter service or roofer | Standing debris holds water and voids substrate warranties |
| Attic and ceiling check | After heavy rain | You | Finds leaks and condensation before they spread |
| Sealant, boot and flashing inspection | Every 3 to 5 years | Metal roofing contractor | Sealants and boots age faster than the metal |
| Exposed screw check and replacement | Every 3 to 5 years after year 10 | Metal roofing contractor | Washers weather and screws can loosen |
| Snow guard and gutter hardware check | Before each winter in snow country | Metal roofing contractor | Loose guards fail under sliding snow |
| Gentle cleaning if needed | As needed | Contractor following the care guide | Removes algae and staining without damaging paint |
Every few years: a professional inspection
Hire a metal roofing contractor, ideally the one who installed the roof, to go over it every three to five years. On an exposed-fastener roof, the big item is the screws: the installer checks for backed-out or missing fasteners, snugs them to the right depth without crushing the washer, and replaces any with washers that have dried or split. On standing seam, the fasteners are hidden, so the visit focuses on the trim and flashings: sealant at the ridge cap and end dams, closures at the eave and ridge, pipe boots, skylight and chimney flashings, and the hems at the eave. On both types, the contractor checks that snow guards are tight, that nothing has been attached to the roof without the right hardware, and that any scratches to bare metal get a dab of the manufacturer’s touch-up paint. Ask for a short written report with photos; it becomes part of the roof’s file and helps with warranty claims and resale.
Cleaning a metal roof
Most metal roofs are cleaned by rain. Pollen, dust and light staining rinse off on their own, and the smooth surface gives moss and algae little to hold. Where a shaded slope or a spot behind a chimney does grow algae or dark streaks, the fix is mild: a solution of water and a gentle detergent, a soft brush or sponge, and a low-pressure rinse, done by a contractor from a ladder or with the right fall protection. Panel manufacturers publish care guides that list approved cleaners, and some allow diluted household bleach for mildew if it is rinsed thoroughly. What they never allow: pressure washing at close range, wire brushes, steel wool, abrasive pads, paint thinners or strong solvents. Steel wool is a special warning, because the tiny steel fibers it leaves behind rust into a field of brown spots that look like roof failure and are not.
Habits that shorten a metal roof’s life
Letting debris sit
Leaves and needles in a valley hold water against the panel and the sealant for months at a time, and wet organic matter is mildly acidic. It is the most common cause of premature corrosion on an otherwise healthy roof, and it is also excluded by most substrate warranties as lack of maintenance.
Mixing metals
Water that has run over copper will corrode steel and aluminum below it, so copper gutters, flashings or decorative pieces do not belong above a painted steel roof. Treated lumber in contact with steel causes the same kind of damage. Lead flashing, wrong-metal fasteners and even a steel ladder scraping an aluminum roof can leave marks. Every accessory added to a metal roof should be compatible with the panel metal, and your installer can tell you what is.
Other trades on the roof
Satellite installers, HVAC technicians, chimney sweeps and solar crews cause more metal roof damage than weather does. They screw brackets through panels, dent flats by walking in the wrong place and lean ladders on gutters and panel edges. Before anyone goes up, tell them it is a metal roof, ask them to walk on the flats near supports and never on seams or ribs, and require that any attachment be approved by your roofing contractor. Our guide to solar panels on a metal roof covers the right way to mount equipment.
Ignoring the small stuff
A cracked pipe boot costs little to replace and a great deal to ignore, because the leak it causes soaks the deck and insulation long before it shows on a ceiling. The same goes for a loose snow guard or a lifted trim piece. Call your contractor when you see something; do not wait for the next scheduled visit.
Keep a roof file
Put the warranty documents, the paid invoice, the permit sign-off, the touch-up paint and every inspection report in one folder. Add a few photos from the ground each year. When something does need attention, that file tells the contractor exactly what is on the roof, and it tells a future buyer the roof was cared for. Our guide to metal roof warranties explains what each document means, and snow retention and gutters covers the hardware that takes the most abuse each winter. If you need a contractor for an inspection or repair, the metal roofer directory lists companies by state and the systems they work on.
Frequently asked questions
How often should a metal roof be inspected?
Look at it yourself from the ground once a year and after any big storm, and have a metal roofing contractor inspect it up close every three to five years, or sooner on an exposed-fastener roof once it passes ten years old. The professional visit covers the things you cannot see from the yard: sealant at flashings and end laps, screw washers, pipe boots, ridge closures and snow guard hardware.
Can I pressure wash my metal roof?
Not at high pressure and not from close range. A pressure washer can drive water under laps and flashings, strip paint at the edges and scratch the finish. If the roof needs more than rain to clean it, a contractor can wash it with a mild detergent solution, a soft brush and a low-pressure rinse. Follow the panel manufacturer's care guide for approved cleaners, and never use wire brushes, steel wool or strong solvents.
Do the screws on a metal roof need to be replaced?
On exposed-fastener roofs, eventually yes. The rubber washer under each screw head weathers over time, and screws can back out slightly as the panels expand and contract. A contractor will check them, snug any that have loosened and replace screws with aged washers, typically some years into the roof's life. Standing seam roofs hide their fasteners under the panels, which is one of the reasons they need less attention.
What should I do about a scratch on a metal roof?
Minor scratches that do not reach bare metal are cosmetic and can be left alone. A scratch down to the steel should be touched up with the manufacturer's touch-up paint, applied sparingly to the scratch only, because touch-up paint ages differently from the factory finish. Have a contractor do it during the next inspection rather than going onto the roof yourself. Deep gouges or creases in a panel are a repair question, not a paint question.
Is moss or algae a problem on metal roofs?
Far less than on shingles, because the smooth surface sheds water and gives organisms little to grip. It can still grow in shaded, damp spots and where debris collects, usually behind chimneys and in north-facing valleys. Keeping debris off the roof and trees trimmed back prevents most of it. If it appears, a gentle cleaning with a manufacturer-approved solution by a contractor removes it without harming the paint.