Metal Roof Noise: Myth and Fact

A common belief is that metal roofs are loud whenever it rains or hails. Industry bodies and manufacturers report that, on typical homes, there is little difference in rain noise between metal and other roofing materials. The perception largely comes from barns, sheds and verandas where thin sheets are fixed directly to open purlins with no deck, insulation or ceiling below.

What controls noise

• Substrate: metal laid over solid plywood, OSB or boarding, with underlayment, is acoustically damped by the deck.
• Insulation and ceiling: attic insulation and interior ceilings absorb and block much of the remaining sound.
• Open framing: exposed-fastener panels over open framing transmit more sound into the space below.

Other noises

Metal roofs can also make ticking, popping or creaking sounds as panels heat or cool. This usually indicates restrained thermal movement, for example panels bound by fasteners, trims or tight clips, and can accompany oil canning. Good detailing that lets panels slide reduces it.

Practical points

• When replacing an older roof, adding or keeping a solid deck and adequate insulation addresses most noise concerns.
• On open buildings, adding insulation under the sheets reduces drumming.

Summary

Noise is a function of the whole roof assembly, not the metal alone. An experienced installer and an appropriate substrate make the largest difference.

Comparison with other materials

The Metal Roofing Alliance, a North American industry group, states that there is little difference between metal and other roofing materials in noise from rain or hail on typical houses. Metal roofs are also reported to weigh about half as much as asphalt shingles, so adding or keeping a solid deck does not usually create structural problems.