Maritimes · Metal vs asphalt
Metal roof vs asphalt shingles
Asphalt costs less today and lasts about 20 years on published averages, and research shows most shingles start losing wind performance between years five and 10; an Interlock® aluminum roof costs more today and is built to be the last roof you buy. For a house you'll keep, compare both written prices over the years you'll own it, counting the next asphalt replacement.
Reviewed by Scott Plumptree, Director of Marketing, The Interlock Group · Updated October 8, 2026
Asphalt
About 20 years
NAHB / Bank of America study, 2007.
Aluminum
Known to last over 100 years
A property of the metal, not a promise.
The Maritimes
5,581 Interlock roofs
In our job book, the first in 1995.
Side by side
| Asphalt shingles | Interlock® aluminum roof | |
|---|---|---|
| Life expectancy | About 20 years (NAHB / Bank of America, 2007) | Aluminum has been known to last over 100 years; a property of the metal, not a promise |
| Material warranty | Varies by brand and line; read who the warrantor is | Guardian Lifetime Limited Material Warranty: material and finish, original purchaser, transferable once |
| Wind | Tabs rely on a sealant strip; most shingles begin to lose wind performance between years five and 10 (IBHS) | Panels lock on four sides; wind warranted to 193 km/h (120 mph) installed to manufacturer specification |
| Salt air and fog | Asphalt doesn't corrode; weathering, wind and freeze-thaw are what wear it out | Aluminum can't rust and absorbs no water |
| Freeze-thaw | Water gets in, freezes and expands; granules loosen and shingles curl and crack as they age | Absorbs no water; nothing for freeze-thaw to open up |
| Snow | Holds snow | Sheds snow; snow guards planned where slides would land |
| At the end | Torn off and sent to landfill, then replaced | Aluminum is recyclable |
| Up-front price | Lower | Higher |
Asphalt life expectancy: National Association of Home Builders and Bank of America Home Equity, Study of Life Expectancy of Home Components, February 2007 (a US study; local weather, design, material quality and maintenance all move it). Asphalt wind ageing: Insurance Institute for Business & Home Safety, September 22, 2026.
Maritime homes that replaced asphalt with aluminum
Recent Interlock® roofs installed in the Maritimes by our own company. Tap a roof to see all of its photos.
Wind is where asphalt loses out here
Research by the Insurance Institute for Business & Home Safety found that most asphalt shingles begin to lose wind performance between years five and 10, and that shingles losing their sealant bond is the single greatest cause. On an exposed Maritimes lot, that is the part of an asphalt roof that a post-tropical storm or a winter coastal storm tests every year.
Storms here can exceed any rating. Fiona, on September 24, 2022, caused over $800 million in insured damage, the most costly extreme weather event ever recorded in Atlantic Canada (Insurance Bureau of Canada). An Interlock® roof's wind resistance is warranted to 193 km/h (120 mph) installed to manufacturer specification; damage from hurricane-force winds is a home insurance matter, not a warranty one, whatever roof you choose.
Is a metal roof worth it in the Maritimes?
The honest answer depends on how long you'll own the house. An asphalt roof costs less today and will be torn off and replaced, likely more than once, while you live there. An Interlock® aluminum roof costs more today and is built to be the last roof you buy.
The way to decide is with real numbers for your house: get a written asphalt price and a written Interlock® price, then compare them over the years you expect to stay, counting the next asphalt tear-off and replacement. Our metal roof cost page shows what Maritimes homeowners have actually paid us recently.
When asphalt is the better choice
- You plan to sell within a few years and the buyer won't pay for the roof.
- The roof's slope is below 3/12 (every Interlock profile needs at least 3/12).
- The budget today simply doesn't allow it, and the current roof can't wait.
If you're replacing asphalt now
Whatever is on the roof now, the inspection decides what comes off. A single layer of asphalt can be roofed over only if our inspection finds it suitable; otherwise it comes off. Ice dams are a separate question from the roof covering: they come from heat loss and ventilation, and ice damming is a stated exclusion of the material warranty, so we look at your attic with you.
Questions, answered
Is a metal roof better than asphalt shingles?
For a house you plan to keep, usually yes: a metal roof sheds snow, absorbs no water for freeze-thaw to work on, and outlasts asphalt, which a 2007 NAHB / Bank of America study put at about 20 years. Asphalt costs less up front.
How long do asphalt shingles last in the Maritimes?
Published averages put asphalt shingles at about 20 years (NAHB / Bank of America, 2007), and local weather, design, material quality and maintenance all move that. Here, wind, salt air, fog and freeze-thaw work on asphalt every year, and IBHS research found most shingles start losing wind performance between years five and 10.
Does a metal roof stand up to hurricanes better than asphalt?
Interlock® panels lock on all four sides with concealed fasteners, with wind resistance warranted to 193 km/h (120 mph) installed to manufacturer specification; asphalt shingles rely on a sealant strip that weakens with age. No roof is storm-proof, and hurricane-force wind damage is a home insurance matter.
Is a metal roof louder than shingles?
Installed over a solid deck and underlayment, as residential Interlock® roofs are, it isn't the drumming of bare metal on an open-framed barn.
Can a metal roof go over asphalt shingles?
Sometimes: a single layer of asphalt can be roofed over only if an inspection finds it suitable. Otherwise it comes off first.
How do I compare the cost of metal and asphalt?
Get both prices in writing and compare them over the years you'll own the home, including the next asphalt replacement. For an Interlock® roof, book a free visit or call (782) 825-6416.
Sources
- National Association of Home Builders / Bank of America Home Equity: Study of Life Expectancy of Home Components (February 2007)
- Insurance Institute for Business & Home Safety: Research reveals critical links in asphalt shingle wind performance after 10 years of aging (September 22, 2026)
- Insurance Bureau of Canada: Insured damages from Hurricane Fiona now over $800 million (January 5, 2023)
- Guardian Lifetime Limited Material Warranty (full terms)
- Interlock Roofing: aluminum shingles, technical specifications
Product specifications are the manufacturer's (Interlock Roofing). Install counts are from our own job book. Reviewed by Scott Plumptree, October 8, 2026.
Get a written price to compare.
A fixed price in writing after one visit, at your home or on Zoom. Maritime Metal Roofing Ltd. · 101 Thornhill Dr #105, Dartmouth, NS B3B 1S2
