How Long Does James Hardie Siding Last?
The warranty gives you one number. The real answer depends on three things you have some control over.
What the manufacturer commits to
James Hardie HZ5 siding carries a 30-year limited, non-prorated product warranty. Non-prorated means the coverage doesn’t shrink year by year over that period. The ColorPlus factory finish has its own 15-year limited warranty, which does reduce over time after the first year. Those are the manufacturer’s written commitments, with conditions and exclusions set out in the warranty document. The warranty guide summarises them.
A warranty isn’t a lifespan. Well-installed fibre cement commonly stays in service longer than its warranty period. We won’t put a figure on that, because it varies from house to house.
Why fibre cement lasts
- It doesn’t rot.
- Insects and woodpeckers get nothing from it.
- It’s non-combustible.
- It’s dimensionally stable, so it doesn’t warp or buckle with temperature swings.
- The HZ5 formulation is made for freezing, wet climates like ours.
The three things that decide it
1. Installation
This is the big one. Boards fastened into framing at the right spacing, proper flashing, correct clearances and treated cut edges are what let the product do its job. Most early failures in fibre cement trace back to how it was put on, not to the board.
2. Exposure
A sheltered north wall has an easy life. A south or west wall takes sun, wind and the worst of the hail. Bottom courses near the ground work hardest of all. Expect different walls to age at different rates.
3. Upkeep
Very little is needed, but that little matters: a rinse once or twice a year, caulking checked and renewed when it fails, soil and snow kept off the bottom edge, and chips touched up. See the maintenance guide.
The finish wears before the board does
Paint is the part with the shorter life. Over the decades you should expect to repaint at least once. The board underneath carries on. That’s quite different from claddings where the colour and the material fail together and the whole lot has to come off. More in repainting.
What shortens its life
- Siding in contact with soil, mulch, decks or roof shingles.
- Missing or poorly done flashing that lets water in behind.
- Failed caulking left for years.
- Sprinklers soaking the same wall every day.
- High-pressure washing.
- Unrepaired impact damage that exposes the board’s core.
How to tell an existing wall’s condition
If you’ve bought a house with fibre cement already on it, look at the bottom edges, the joints, the caulking round windows and the paint on the sunny side. Solid boards with tired paint mean the siding has plenty of life left and needs a repaint. Swollen or crumbling edges mean moisture has been getting in and the cause needs finding.
Not sure what you’re looking at? Ask for an inspection.