James Hardie vs. Metal and Aluminum Siding: An Honest Comparison

We install both. That changes the answer.

Most siding comparisons are written by companies that sell one product. We install James Hardie fibre cement and we install metal and aluminum siding, so we have no reason to talk you out of either.

The short version: for a traditional GTA home with wood trim and a pitched roof, Hardie is the better default. For a contemporary elevation with long horizontal lines and large glazing, metal is often the right answer and Hardie is the wrong one. Here is why, including the parts that are inconvenient for anyone selling Hardie.

What each material actually is

Fibre cement. Cement, sand, cellulose fibre and water, plus proprietary additives. Formed under pressure, textured, cured, then cut. It is not extruded; that is vinyl. HardiePlank lap is 5/16 in. thick, Artisan lap 5/8 in., HardieShingle 1/4 in. Hardie manufactures to ASTM C1186 Grade II Type A, the exterior exposure classification, and the companion ASTM C1185 regime includes freeze-thaw testing for cladding.

Canada gets the HZ5 cold-climate line, which Hardie describes as having an engineered surface for "higher performance, giving it superior paint adhesion and moisture resistance," plus "a drip edge to provide improved water management."

Metal and aluminum. A formed metal panel with a factory finish, across a wide quality range. At the premium end, one aluminum system evaluated under ICC-ES ESR-4182 (Longboard) uses 6063-T5 alloy at 1/16 in. (1.59 mm), with panel lengths up to 24 ft. Residential products like Kaycan aluminum sit in a different tier.

Where metal genuinely wins

Long, unbroken lines

Panel lengths to 24 ft mean you can wrap a modern facade with almost no visible seams. Fibre cement comes in shorter planks and needs butt joints, sealed with ASTM C920 Grade NS Class 25+ or ASTM C834 latex sealant. On a traditional home those joints disappear into the shadow lines. On a minimalist elevation they read as clutter.

Wind load

That evaluated system carries an allowable wind load of 121 psf, positive and negative. Typical residential design wind pressure runs roughly 20 to 40 psf, so 121 psf is several times what the wall is designed for. On an exposed lakefront lot or a tall unsheltered wall, that headroom is real.

No repainting, with a strong finish warranty

Metal's biggest practical advantage. Premium powder-coated aluminum can carry a 50-year non-prorated profile warranty plus a 15- or 20-year non-prorated finish warranty. At the top tier that finish coverage includes materials, labour, removal and reinstallation. The powder is AAMA 2604 or 2605 certified.

PVDF finishes, commonly called Kynar, are a separate chemistry from powder coat. They are typically warranted to hold colour change within 5.0 Hunter deltaE units per ASTM D2244 and chalk resistance to ASTM D4214 rating 8 or better. Ask which of the two you are buying.

Colour, geometry and fire

Metal does true metallic finishes, deep saturated colours and crisp machine-made profiles, including matching soffit. Hardie's ColorPlus is very good, but premium metal finishes are the benchmark for colour hold. Aluminum is noncombustible per ASTM E136, and with powder coating it comes in under 25 flame spread and 450 smoke per ASTM E84, qualifying as noncombustible under 2024 IBC 703.3. It is also lighter and faster to install than fibre cement.

Where metal has real limitations

Aluminum dents, and dents are permanent. This is installer experience, not test data, and it is the most common regret we see. Aluminum is soft. A ladder, a hockey puck, a lawnmower stone: the dent stays. You replace the panel, and on a long-panel system that is a bigger job than swapping a plank. Fibre cement can crack under a hard enough hit, but it does not deform and stay deformed.

Oil-canning. Wide flat metal panels can show a subtle waviness that catches raking light. It is a characteristic of flat metal, not a defect, and narrower reveal profiles reduce it. If your elevation takes low afternoon sun, see the profile on a real building first.

Visible thermal movement. Metal expands and contracts more visibly than fibre cement. Good detailing accommodates it, but on long runs you will see it.

No insulating value. Metal contributes essentially none, and neither does fibre cement.

Residential-tier warranties are narrower than they sound. Kaycan's 25-year aluminum warranty states the product "will not rust, burn, split or crack due to cold weather or lose impact resistance." Years 1 to 10 non-prorated, years 11 to 25 prorated, original homeowner only, not transferable, and it excludes labour, hail, wind-borne objects and collision. Reasonable for its tier, but not the premium 50-year document above. Kaycan's system also uses a thermoset polyester coating rather than PVDF. Polyester is decent; PVDF is substantially better. That is Kaycan specifically, not the whole industry.

Where James Hardie wins

It looks like wood, because of how it is made. Formed under pressure, fibre cement holds real wood-grain texture and genuine shadow lines that metal cannot imitate. On a traditional GTA home that is the whole argument. A colonial clad in flat metal panels reads as commercial. The same house in HardiePlank looks like it was always meant to be there.

Fire performance on the board. Noncombustible per ASTM E136 and Class A per ASTM E84, flame spread 0 and smoke developed less than 5, per ICC-ES ESR-2290 and ESR-1844. James Hardie adds its own caveat: that performance belongs to the board, not the coating. Paint may char in direct flame even though the substrate will not ignite.

A stricter Canadian spec. HZ5 install requirements here are tighter than the US version: 8 in. siding-to-ground clearance versus 6 in., and 1/2 in. versus 1/4 in. in sheltered areas. Small numbers, large effect on how a wall handles snow and splash-back.

A transferable warranty. Hardie carries a 30-year non-prorated limited substrate warranty on siding, trim and soffit, and it transfers to the next owner. ColorPlus Technology, a factory-applied finish baked on and cured between coats, carries a 15-year limited warranty covering paint and labour against peeling, cracking and chipping. Fading is a performance claim, not a warranted item.

Resale evidence. In the 2025 Cost vs. Value Report from Zonda and JLC (US national averages in USD, not Canadian data), fibre-cement siding replacement recouped 114 percent: $21,485 spent against $24,420 in resale, 4th of 28 projects. Vinyl recouped 97 percent. Directional here, not local.

What it costs you. More labour than vinyl or aluminum, because it is heavy. Cutting generates crystalline silica dust requiring proper tooling and dust collection; James Hardie maintains a formal silica safety program and any competent installer follows it. Sealed joints are a maintenance item.

At a glance

How we decide on a site visit

Roof first. Pitched with visible trim? Hardie. Flat or low-slope with a parapet? Metal. Then exposure: tall unsheltered walls suit metal's wind numbers, walls beside a driveway suit a board that does not dent. Many of the best projects use both, Hardie on the main volume and metal on a modern rear addition or soffit.

Common questions

Is metal siding a worse product than fibre cement?

No. Premium metal has a stronger finish warranty than Hardie's and wind numbers well beyond residential design pressure. It is a different product for a different kind of house. We recommend Hardie more often here because most GTA housing stock is traditional and fibre cement's wood texture suits it. That is an aesthetic judgement, not a quality ranking.

Will aluminum siding dent in a hailstorm?

Aluminum is soft and dents permanently and visibly. Kaycan's 25-year warranty also specifically excludes hail, wind-borne objects and collision. We will not quote an impact rating for Hardie either, because we do not state numbers we cannot back up. If dent resistance is a priority, that argues for a rigid board.

Does either material make my house warmer?

No. Metal contributes essentially no insulating value, and fibre cement is not an insulating product either. Thermal performance comes from the wall assembly behind the cladding, and a re-clad is a good moment to improve it.

Which warranty is actually better?

They protect different things. Hardie: 30-year non-prorated transferable substrate, plus 15-year ColorPlus coverage on paint and labour. Premium powder-coated aluminum: 50 years non-prorated on the profile, 15 or 20 years non-prorated on the finish including labour, removal and reinstallation at the top tier. Metal's finish coverage is stronger; Hardie's transferability matters at sale. Read the document for the product you are quoted, not the category.

Can I use both on one house?

Yes, regularly. The detailing where the two meet has to be planned at design stage, not solved on site.