Ask how long siding lasts and you get two answers that differ by decades. Both are correct. They’re answering different questions.
Answer one: it lasts as long as the house
InterNACHI’s Standard Estimated Life Expectancy Chart — the reference home inspectors use — puts brick, vinyl, engineered wood, stone and fiber cement in the same category: they last as long as the house does, under normal wear and maintenance.
That is a statement about the material. Vinyl does not rot. Fiber cement does not decay. Brick and stone outlast the people who install them. As a matter of physical durability, siding is one of the more permanent things on a home.
Answer two: 20 to 40 years
Consumer replacement data tells a different story. Wood typically gets 15 to 40 years, aluminum 20 to 40, vinyl 30 to 40, brick 50 to 100, and stone past 100. Cheaper vinyl can warp within a decade.
Typical replacement windows by material. Sources disagree with inspection standards — see below.
Replacement windows from Today’s Homeowner, 2025. Material durability from InterNACHI’s Standard Estimated Life Expectancy Chart.
Why the gap exists
Siding almost never fails all at once.
It fades. A few panels crack after a hailstorm. A corner works loose and nobody notices for a season. The colour that looked current in 2005 doesn’t now. None of that is failure in the engineering sense, and all of it is why people call a siding contractor.
So the practical replacement window isn’t a measure of when siding stops working. It’s a measure of when homeowners stop wanting to look at it — or when a storm makes the decision for them.
That distinction matters when you’re deciding whether to replace. A wall that is structurally fine but faded is a different decision from a wall that is letting water into the sheathing. The first is discretionary. The second isn’t.
What actually shortens it
Four things move a siding lifespan more than the material choice does.
Installation quality. Vinyl has to be hung so it can expand and contract. Nailed too tight, it buckles in summer heat. This is the single most common cause of premature vinyl failure, and it has nothing to do with the product.
Moisture behind the wall. The siding is a rain screen; the weather barrier underneath does the waterproofing. When the barrier is compromised — bad flashing, a failed seal around a window — the siding can look perfect for years while the sheathing behind it rots.
Sun exposure. South and west elevations fade first and fade hardest. Dark colours fade fastest. It is normal for one wall of a house to look a decade older than the others.
Freeze-thaw cycling. Materials that expand and contract through repeated freezing take more punishment in northern markets than in mild ones.
When to replace rather than repair
A few cracked panels are a repair. Replace when the pattern suggests the wall underneath is involved:
- Soft or spongy spots when you press on the wall
- Panels loose or missing across multiple elevations, not one
- Interior signs — staining, bubbling paint — on an exterior wall
- Fading severe enough that replacement panels can’t be colour-matched
That last one is worth knowing before you start. On an older faded wall, a partial repair often looks worse than the damage did, because new material won’t match what the sun has already done to the rest.
For what a replacement costs by material, size and market, see the siding cost guide.
