Is a Metal Roof Noisy in the Rain?

Victoria rain is mostly the quiet kind. December's 109 mm at Gonzales arrives over many days of steady drizzle rather than as tropical downpours, so the loudest thing a metal roof here usually hears is a squall driving in off the strait at Dallas Road or Cordova Bay. The homes where owners do report rain noise are a specific type: 1960s and 70s post-and-beam houses in Gordon Head, Ten Mile Point and Cordova Bay with vaulted tongue-and-groove ceilings, no attic and a few centimetres of rigid insulation between the ceiling boards and the roof deck. On those, any roof is audible and metal is a little more so.

The rest of the housing stock is on the quiet side of the line. Fairfield and Oak Bay character homes have deep attics; Langford, Westhills and Royal Bay houses have trussed roofs with blown-in insulation; Broadmead and Highlands owners who went to metal to beat the moss rarely mention noise. What they do notice is different: the tick of panels expanding on a sunny afternoon, fir cones landing from an overhanging tree, and wind humming at a ridge cap on an exposed site. Those are installation and site questions, not reasons to avoid metal.

Sound needs a panel free to vibrate and an empty space to ring in. A farm building gives it both: thin sheet screwed to purlins a metre apart, nothing underneath. A house roof gives it neither. The panel is fastened to plywood or strapping over plywood, an underlayment sits between metal and wood, the attic below holds a thick blanket of insulation, and the ceiling is drywall. Each layer removes energy from the sound before it reaches the room. The Metal Roofing Alliance's guidance is blunt about it: rain noise is a symptom of missing underlayment or insulation, not a property of metal.

A few local house types and details are worth flagging before you choose metal, because they are the ones that generate the complaints.

• Vaulted post-and-beam ceilings from the 1960s and 70s with no attic cavity; consider adding rigid insulation above the deck as part of the re-roof
• Exposed-fastener agricultural-style panels installed on strapping with an air gap, a common budget approach that trades quiet for cost
• Carports, covered decks and sunrooms, where you sit directly under the roof
• Bedrooms directly under a low-slope section with a thin roof assembly
• Skylight curbs and dormer cheeks, where panel edges meet and can rattle if not fastened to spec

Metal moves with temperature. On a sunny afternoon and again as it cools at night, panels expand and contract, and a roof with fixed clips or over-tight fasteners can tick or pop; floating clips on standing seam and correct fastener torque prevent most of it. Wind can hum at a ridge or eave closure that was left open; foam closures fix that. Debris is the last one: cones, branches and acorns from the Garry oaks and firs that shade so many Saanich roofs land audibly on metal where they would thud on shingles. None of these is a defect in the material; each has an installation answer.

Put these in the scope and the noise question is settled before the first panel goes up.

• Direct-to-deck installation on solid sheathing, not over strapping with an air gap, unless the manufacturer requires strapping
• A synthetic or high-temperature underlayment across the whole deck
• Concealed-fastener standing seam or interlocking metal shingles rather than exposed-fastener panels over living space
• Attic insulation topped up to current levels while the roof is open; on vaulted ceilings, rigid insulation above the deck
• Foam closures at ridge and eaves, and floating clips on long standing seam runs