Siding Cost: Vinyl, Fiber Cement and James Hardie

Siding is sold and quoted by the square - 100 square feet of wall - and almost every online estimate hides that behind a single national average. The average is not about your house. Build the number instead: get your net wall area, turn it into squares, and price each layer.

The price is four lines, not one

siding cost = squares × material rate
            + trim (J-channel, corners, starter)
            + labor
            + tear-off and repairs (if any)

Run your walls through the siding calculator to get the first line - it takes the gable ends, subtracts the doors and windows, and gives you the net area, the squares, and the trim lengths. Then price each line locally. Rates move by market, by season and by how busy the crews are, so a figure you look up is a starting point, not a quote.

What actually moves the total

Three things shift a siding budget more than the size of the house does:

• The material. This is the single biggest lever, and the spread is wide - see the table below.
• The openings and the detail. A crew is paid for hours, not for area. Windows, corners, dormers and a steep gable all mean more cutting, more trim and more scaffold, on a wall that measures the same square footage as a plain one. A small fussy house can cost more per square foot than a big plain one.
• Tear-off. Stripping old siding, and whatever the crew finds behind it, is the line most likely to move after the quote. Rotten sheathing is the classic surprise.

The materials, cheapest to dearest

Two things worth being clear about, because most cost pages blur them:

James Hardie is fiber cement. It is a brand within the category, so “fiber cement vs Hardie” is not a materials question - it is a product question. Quote Hardie against another fiber cement board on the same wall and the gap narrows.

Fiber cement’s premium is mostly labor. The board costs more, but the bigger difference is that it is heavy, it needs a shear or a scoring tool, and it is a two-person lift. That is why the installed gap is wider than the material gap.

Cost per square foot, and why it misleads

Per-square-foot is how siding gets advertised and it is the least reliable number in the job, because it silently bundles the material, the trim, the labor and the difficulty of the wall into one figure. Two houses on the same street can be a dollar apart per square foot on the same product.

Use it as a sanity check on a quote, never as the basis for a budget. The reliable path is the other direction: price your own material and trim, add a local labor rate, and divide by your area at the end. The per-foot number that falls out is about your house.

Worked example

A two-story house with 2,400 sq ft of gross wall, 340 sq ft of windows and doors:

1. Net area: 2,400 - 340 = 2,060 sq ft.
2. Squares: 2,060 ÷ 100 = 20.6 squares. Add wastage - call it 10% for a plain wall, more if there are a lot of cuts - so ~23 squares to buy.
3. Material: 23 × your local rate per square.
4. Trim: the calculator gives the J-channel and corner-post lengths - price these separately, because a quote that looks cheap on panels often makes it back here.
5. Labor: commonly around half the installed price, and it goes up with the gables and the window count, not the area.
6. Tear-off: only if the old siding is coming off, and leave room for what is behind it.

Change nothing but the material in step 3 and the total moves more than any other single edit you can make - which is the whole argument for pricing the material first.

DIY versus installed

Vinyl is the one mainstream siding a determined homeowner genuinely does hang, and since labor is roughly half of an installed price, that is a large saving. Fiber cement is a harder proposition: it is heavy, cutting it makes silica dust that needs proper protection, and it is unforgiving to hang badly on a wall you have to look at for thirty years.

The materials cost the same either way. The question is whether you have the time, the gear and a second pair of hands - and, for two stories, whether you are comfortable working off staging.

Where siding estimates go wrong

• Quoting off gross wall area. The openings come off. On a house with a lot of glass that is a real number.
• Forgetting the trim. J-channel, corners and starter strip are a separate purchase and a separate line on a quote.
• Reading a national average as a quote. It is an average of markets, houses and materials that are not yours.
• Assuming Hardie is a different material from fiber cement. It is fiber cement. Compare it against other boards in its own category.

Start with the siding calculator for the squares and the trim, then read vinyl vs fiber cement siding if you have not settled the material - because that is the decision the price is actually waiting on.