What Looking After a Metal Roof Actually Involves

Metal roofs are sold as low maintenance, and compared with most alternatives that is fair. But low maintenance is not no maintenance, and the owners who get the full life out of a metal roof are the ones who know what the small jobs are.

The good news is that they are small, and most of them cost nothing but a look.

Once or twice a year

A walk around the house in spring and again in late autumn covers most of it. From the ground, with binoculars if the roof is high:

• Valleys and behind chimneys. Leaves and needles collect where two slopes meet and on the uphill side of anything that sticks through the roof. Debris that stays wet holds moisture against the panel, which is how staining and corrosion start.
• Eavestroughs and downspouts. Blocked troughs overflow behind the fascia and into the soffit. Cleaning eavestroughs covers how often and what to check.
• Anything loose or out of line. A trim piece that has lifted, a snow guard that has moved, a vent boot that looks cracked.
• Overhanging branches. Branches that touch the roof scrape the coating every time the wind blows.

Every few years

Some components age faster than the panels.

• Sealants at penetrations. Plumbing vent boots, chimney flashings and skylight surrounds use materials that do not last as long as steel. They are cheap to deal with early and expensive to deal with after a leak.
• Exposed fasteners, if your roof has them. On exposed-fastener systems the washers under the screw heads age in the sun. Concealed or exposed fasteners explains the difference and why it matters for upkeep.
• A look at the coating. Scratches from a falling branch or a careless tradesperson are worth touching up with the correct paint before they become rust. Rust on a metal roof covers where it starts.

Cleaning

Most metal roofs never need cleaning beyond what rain does. Roofs under heavy tree cover, or on the shaded north side of a cottage, can grow moss or pick up staining. That is cosmetic at first but worth dealing with properly, and properly means gently. Moss, streaks and staining covers what to use and what to avoid.

What owners do that causes damage

A surprising share of the problems we see on metal roofs were caused by someone trying to help.

• Pressure washing. Too much pressure can damage the coating and drive water past laps and trims.
• Walking on the panels in the wrong places. Many profiles can be dented by stepping between their supports. If someone has to go up, they should know where to put their feet.
• Abrasive cleaners and wire brushes. These take off the finish you are trying to protect.
• Fixing things through the panels. Antennas, satellite dishes, light fixtures and Christmas lights screwed through the roof make holes the roof was never designed to have.
• Chipping at ice. If ice builds up, the answer is to understand why. Ice dams explains what a roof can and cannot fix.

What it costs

For most homes, the ongoing cost of a metal roof is close to nothing in a typical year and a modest repair bill once in a while. That is a large part of why a metal roof can cost less over its life despite the higher price at the start.

Highland does inspections, cleaning and repairs, including on roofs we did not install. If something on your roof has caught your eye, tell us what you have seen.