Does metal roofing really last twice as long as asphalt in Victoria?

The lifespan gap is widest on the region's shaded lots. In the Highlands, Broadmead and the fir-covered parts of Metchosin, asphalt roofs under a canopy are often done in 15 years because moss lifts the shingles and holds water against them, while a standing seam roof on the same lot sheds needles and moss and simply keeps going. Many homeowners there choose metal for the second roof precisely because they watched the first asphalt roof fail early.

Salt is the local factor that can shorten metal. Cordova Bay bluffs, Dallas Road, Esquimalt harbour and Sidney's waterfront put spray on the roof, and a galvanised panel with a standard coating will not see 40 years there; aluminum or a coastal-grade coated steel with matching fasteners will. The 'twice as long' claim assumes the metal was specified for the site, which is a question to put to any installer quoting near the water.

Asphalt shingle life is set by the binder drying out, granules washing off and, in Victoria, moss prying the tabs up; manufacturers quote long limited warranties but local roofers and realtors see 15 to 25 years in practice. Metal does not have a binder to age. Coated steel and aluminum panels fail through coating breakdown, fastener corrosion or sealant at penetrations, all of which are slow and mostly visible. That is why industry guidance runs 40 to 60 years and a Victoria contractor cites 40 to 50 locally.

The honest caveat is that few Greater Victoria residential metal roofs are old enough to have proven a 50-year life on this coast; the figures are engineering expectations plus the record of older commercial and rural roofs.

Metal is not immortal, and the failures are specific.

• Salt spray on standard galvanised steel near the water; specify aluminum or coastal-grade coatings
• Mismatched fasteners or flashing metals causing galvanic corrosion
• Exposed-fastener panels whose washers harden after 15–20 years and need replacing
• Sealant at pipe boots, skylights and wall flashings drying out; a maintenance item every few years
• Foot traffic denting panels or scratching coatings
• Poor detailing at valleys and penetrations, which no lifespan figure survives

Divide our model's midpoints by the local lifespans and the two materials land surprisingly close: asphalt at roughly $9,800 over 18 years is about $540 a year, metal at roughly $22,700 over 45 years is about $500 a year, before maintenance and before the second asphalt tear-off and disposal that the metal owner never pays. Add the moss treatments a shaded asphalt roof needs every 12 to 18 months and metal pulls ahead on those lots.

The comparison reverses if you plan to sell within a decade: a realtor guide estimates a new roof recoups about 60–70% of its cost at sale, and a metal premium is recovered even less predictably.