Are Metal Roofs Loud in the Rain?

It is the first thing people say when metal roofing comes up. Is it not incredibly loud when it rains?

The reputation is real and it comes from somewhere real. It is just that the somewhere is a barn, and you do not live in a barn.

Where the reputation comes from

Think about where most people have actually stood under a metal roof in the rain. A farm outbuilding. A garden shed. A carport. A cottage bunkie.

What those structures have in common is that there is nothing between the metal and your ears. The sheet is fixed to open purlins, the underside of the roof is the ceiling, and the whole thing behaves like a drum skin with an air cavity behind it. It is loud, and it is loud for a good reason.

A house is not built that way, and neither is a properly built metal roof on a house.

What actually sits between you and the rain

On a house, a rain drop that hits the panel has to get through the whole roof assembly before it reaches you as sound. In order, that is typically:

• The panel itself, which is not a free-hanging sheet but fixed down along its length.
• The strapping and the underlayment.
• A solid roof deck of plywood or board.
• The attic void, which is a large volume of air.
• The insulation lying on the attic floor.
• The ceiling below it.

Each of those layers absorbs and disrupts sound. By the time noise from the panel reaches a bedroom, most of what made it loud has been dealt with by the deck, the attic and the insulation, none of which exist in a shed.

This is why the honest answer to the question is not really about the metal at all. It is about what the metal is attached to.

Where you genuinely will hear it

There are situations where a metal roof is audible, and pretending otherwise helps nobody. The common factor in all of them is a missing layer.

• Cathedral and vaulted ceilings. No attic void, so one of the biggest sound buffers is simply not there. The insulation strategy matters much more in these rooms.
• Sunrooms and three-season rooms. Often lightly built with a thin or absent ceiling.
• Detached garages, workshops and bunkies. Frequently no ceiling and no insulation, which is the barn situation again.
• Open-plan cottages with exposed roof structure. Beautiful, and acoustically the least forgiving thing you can build.

If your house has one of these, say so when you get a quote. It is a design question with real answers, and it is much cheaper to solve during the roof than afterwards.

Hail and wind, while we are here

Hail on a metal roof is audible, in the same way hail on anything is audible, and it is over in a few minutes. Wind is the more interesting one: a correctly fixed metal roof is quiet in wind, because the panels are secured along their length rather than being individual tabs. Where people hear wind noise on a metal roof, it is usually loose trim or flashing rather than the panels, and it is a repair rather than a characteristic.

What to ask your roofer

If noise is genuinely on your mind, these three questions get you a useful answer.

• Is my roof going onto a solid deck, and is the existing deck in good enough condition?
• What is going between the panels and the deck?
• Do I have any rooms without an attic above them, and what would you do differently there?

A roofer who answers those specifically is telling you how they build. A roofer who just says it will be fine is telling you something too.

Highland has been installing metal roofs across the Greater Toronto Area and cottage country since 2004. If you want to talk through your own house, including any rooms you are worried about, request a quote and mention it.