Metal Siding vs Fibre Cement: Weight, Water and Maintenance
Fibre cement does not dent and takes paint beautifully. Metal does not absorb water and never needs repainting. The real differences are in weight, cutting, joints and how each one handles moisture.
Fibre cement is the other serious contender when a homeowner rules out vinyl. It is a genuinely good product — dimensionally stable, non-combustible, takes a factory finish well, and available in far more textures and profiles than metal. It also has specific weaknesses that metal does not share, and vice versa. This is a comparison of mechanisms, not marketing.
What Each Material Actually Is
Fibre cement is portland cement, sand and cellulose fibre, formed into boards and cured. It is a cementitious product with wood fibre in it, and it behaves like one: dimensionally stable in the dry, but capable of absorbing water, and vulnerable at any place water can sit.
Metal siding is coil steel or aluminum, metallically coated and then finished with a factory-applied paint system, roll-formed into a profile. It absorbs no water at all. It is impermeable to vapour, which is both its greatest advantage and the source of its main design constraint.
Moisture: The Central Difference
Fibre cement will take on water. The face is protected by a factory coating, but every cut edge is raw material, and the bottom edge of every plank sits where water runs off. Manufacturers require cut ends to be sealed and edges kept clear of the ground and of hard surfaces for exactly this reason. Where water sits at a butt joint or wicks up from splash-back, the board absorbs moisture, and Ontario's freeze-thaw cycling then works on that saturated material. Over years this shows up as swelling at the joints, edge deterioration at the bottom course, and paint failing along the edges first.
Metal has no such failure mode. It does not wick, swell or delaminate. What it has instead is the impermeability problem: any water that gets behind a metal panel cannot dry outward through it, because metal is a vapour barrier. That water has to leave via the drainage cavity. This is why a drained, vented cavity behind metal siding is not an upgrade — it is how the assembly is supposed to work.
Both materials need a properly drained wall behind them, for different reasons. Fibre cement needs it so the board can dry from both faces and so its edges are not sitting in water. Metal needs it because it cannot dry outward at all and depends entirely on the cavity. Neither should be applied direct to sheathing on an Ontario wall as a matter of habit.
Joints and How They Age
Fibre cement lap siding produces butt joints wherever two planks meet in a course. Best practice is a joint flashing behind every butt joint, boards gapped rather than jammed tight, and joints staggered course to course. Done well, it works. Done poorly — joints butted tight, no flashing, ends caulked as the only defence — those joints are where the wall fails first, because caulk moves, cracks, and lets water into the exposed core.
Metal handles joints differently. Concealed-fastener systems either lap the panels or die them into a formed trim, and the panel is designed to move within that joint rather than be sealed into it. There are still joints to get right, but there is no absorbent core waiting behind them if a joint lets water past.
Weight, Handling and Labour
This is a substantial practical difference. Fibre cement is heavy — a plank is dense, and a full elevation is a lot of mass to lift. Long planks need two people to handle without cracking. Metal panels of equivalent coverage weigh a fraction as much, and a single installer can manage lengths that would need a crew in fibre cement.
- ✓Fibre cement is heavy enough that fastening, staging and handling all have to account for it, particularly on upper storeys.
- ✓Metal is light enough that wind handling during installation becomes the concern instead — a long panel is a sail.
- ✓Fibre cement can crack if flexed or dropped on a corner; metal kinks instead, which is equally permanent but less likely on site.
- ✓Fibre cement is generally more forgiving of a slightly irregular substrate, because the boards are thicker and stiffer and there is no large flat metal face to show waviness.
Cutting: Dust Versus Swarf
Cutting fibre cement produces respirable crystalline silica dust. This is a recognized health hazard, and it is why manufacturers specify shears, scoring, dust-collecting saws or wet cutting, along with respiratory protection. A crew cutting fibre cement dry with a circular saw on a still day is doing something genuinely unsafe. It also means dust on the neighbour's cars, the windows and the landscaping.
Metal cutting is cleaner in that respect — shears and nibblers produce no dust at all. The metal equivalent of the dust problem is swarf: hot steel filings from an abrasive wheel embed themselves in the paint finish and rust into orange freckles across the panel. The fix is to avoid abrasive cutting entirely, cut with shears or a fine-tooth blade, and sweep filings off panels and trim the same day.
Finish and Maintenance Over Time
Factory-finished fibre cement holds paint very well — the substrate is stable and does not move much with moisture, which is precisely why paint lasts longer on it than on wood. But it is still paint on a porous substrate, and the expectation over a long ownership is that the wall will be repainted at some point. Field-painted fibre cement needs it sooner.
A quality metal coating on a non-absorbent substrate holds colour and gloss for a very long time and is not expected to be repainted on the same cycle. That is a genuine advantage, but it is not zero upkeep: metal walls should be washed periodically to remove road salt and grime, cut edges and scratches need attention, and exposed-fastener systems have washers that age. Coating quality varies widely between products, and the finish warranty document is where the actual commitment is written down — read it rather than relying on a summary.
Appearance and Design Range
Fibre cement wins on variety. It comes in lap, panel, shingle and board forms, in smooth and wood-textured surfaces, in a wide range of factory colours, and it can be painted any colour you like. It reads as a painted wood-like surface, which suits traditional Ontario architecture well.
Metal's range is narrower but distinct: standing seam, board-and-batten, corrugated and flush panel are looks fibre cement cannot produce. It reads as metal, which is either exactly what you want or exactly what you do not. Wood-grain printed metal exists and is a reasonable compromise at a distance, but it does not stand up to close inspection the way real texture does.
Cost
Metal siding typically costs more upfront than fibre cement, with the gap widening for architectural systems like standing seam and flush panel. Fibre cement's material cost is moderate but its labour is not cheap — the weight, the cutting precautions and the joint detailing all take time. Where the two get close is on high-end fibre cement installations with extensive trim work. The honest summary is that neither is the budget option; vinyl is.
Frequently Asked Questions
Does fibre cement dent like metal?
No. It is rigid and does not deform under impact. It cracks or chips instead, particularly at corners and edges, and a cracked board exposes the absorbent core to water. Metal dents but stays weathertight. Pick your failure mode based on what the wall is likely to encounter.
Which is better for a house near a road that gets salted in winter?
Both need attention, and the answer is more about detailing than material. Keep the bottom of the cladding well above the splash and snow-pile zone in either case, and wash the lower wall in spring. Fibre cement's exposed bottom edge is the vulnerable point; on metal, it is any scratch through the coating in the splash zone.
Can the two be combined on one house?
Yes, and it is a common and effective approach — fibre cement on the main field with metal on gables, a feature volume or the base, or the reverse. The transition needs a properly flashed detail with a drip, and both claddings need their own continuous drainage path behind them.
Which one is easier to repair?
Fibre cement, for damaged boards, though matching a weathered painted finish is its own challenge. Metal panels in a locked run can require working back from a trim, so keeping spare panels from the original order is worthwhile. Neither is as simple as vinyl.
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