LP SmartSide is worth quoting when engineered-wood siding and longer lap boards suit the job. James Hardie is worth quoting when the project calls for noncombustible fiber-cement siding. Compare the same profile, exposed width, finish, and installation scope before deciding which costs less.
For a homeowner, the choice affects appearance, maintenance, and the total bid. For a contractor, it also affects board handling, cuts, fastening, finishing, and the labor allowance. Here's what to compare before either quote goes out.
Sources checked November 1, 2026. This compares LP SmartSide lap siding with Hardie Plank fiber-cement lap siding, not every product either company makes. Examples use stated dimensions and illustrative USD prices, not local bids or hands-on testing.
LP SmartSide vs Hardie at a glance
| Factor | LP SmartSide lap siding | Hardie Plank lap siding |
|---|---|---|
| Material | Treated engineered wood | Fiber cement |
| Length to check | LP's catalog lists standard 16-foot lap products | Many Hardie Plank products are supplied in 12-foot lengths; verify the regional SKU |
| Finish options | Primed or factory-finished ExpertFinish | Primed or factory-finished ColorPlus |
| Installation planning | Allow for specified joints, cut-end treatment, clearances, and fastening | Allow for specified joints, clearances, fastening, handling, and silica dust controls |
| Fire consideration | Don't assume an engineered-wood product meets a noncombustible-material requirement | Hardie identifies its fiber cement as noncombustible under ASTM E136 |
| Warranty comparison | 5/50 limited substrate coverage; separate finish coverage for ExpertFinish | 30-year non-prorated limited substrate coverage; separate ColorPlus finish coverage |
Product references: LP SmartSide catalog, Hardie regional product catalog, and Hardie's fire-performance explanation. Dimensions and availability vary by product and region.
Which is cheaper? Start with coverage, not board price
A 16-foot board and a 12-foot board don't cover the same area. Neither does a wider board necessarily cover its full face width once installed. For lap siding, calculate using the exposure, the part of each course left visible after the overlap.
Example: a seven-inch exposure
Assume the selected products both permit a seven-inch exposure under their installation instructions. This is a comparison exercise, not permission to use that exposure on every SKU.
| Calculation | 16-foot lap board | 12-foot lap board |
|---|---|---|
| Coverage at 7-inch exposure | 16 × 7 ÷ 12 = 9.33 sq ft | 12 × 7 ÷ 12 = 7 sq ft |
| Example price per board | $18 | $15 |
| Example cost per covered sq ft | $1.93 | $2.14 |
The $18 board has the lower material cost per covered square foot in this example. That doesn't establish a brand-wide price advantage: replace $18 and $15 with quotes for matching finishes, profiles, and grades.
Now assume 1,000 square feet of net siding area, with an illustrative 10% cutting and waste allowance. Your preliminary order covers 1,100 square feet:
- 16-foot option: 1,100 ÷ 9.33, rounded up using the unrounded coverage, is 118 boards. At $18 each: $2,124.
- 12-foot option: 1,100 ÷ 7, rounded up, is 158 boards. At $15 each: $2,370.
That's a $246 material difference before tax, delivery, trim, or installation. At an assumed loaded labor cost of $55 per person-hour, roughly 4.5 extra person-hours would consume that saving. The crew's actual handling and installation time matters more than a small difference on a shelf tag.
Use a wall-by-wall layout before ordering. Openings, gables, permitted joint locations, usable offcuts, and damage can change quantities. Ten percent is a budget assumption, not a universal waste factor. The siding cost calculator can help organize the wider estimate.
Installation: where the bids can diverge
LP lists 16-foot lap boards, which can reduce joints on suitable walls. Longer stock also needs space to unload, stage, and handle. Don't promise a fixed labor saving without considering the elevation and your crew. LP product catalog
For SmartSide, confirm the exact series and finish. Primed lap and ExpertFinish can have different joint and finishing instructions. Price the required cut-end treatment, flashing, clearances, and fastening instead of copying the detail from another product. LP lap installation instructions
For Hardie, select the applicable product and regional installation guide. Include suitable handling and cutting equipment in the labor plan. Cutting fiber cement can create respirable crystalline silica; use the manufacturer's safety guidance and the required controls for your work method. Hardie installation documents, silica safety resources
For either product, the siding is only part of the exterior assembly. Water-resistive barrier, flashing, trim, penetrations, and clearances need their own details and costs. A low siding price doesn't make up for missing water-management work.
Primed versus factory-finished: match the scope
A primed product still needs its specified finish. Don't compare a primed-board material price with a factory-finished installed quote and call the first option cheaper.
Ask for these items in both bids:
| Quote line | What to make explicit |
|---|---|
| Siding | Manufacturer, series, profile, texture, exposure, and quantity |
| Finish | Primed plus field painting, or the named factory finish and color |
| Trim | Corners, window and door trim, fascia, and any matching finish |
| Wall preparation | Removal, disposal, sheathing repairs, and water-resistive barrier |
| Installation | Flashing, fasteners, sealants where required, access equipment, and labor |
| Completion | Touch-up work, cleanup, delivery, tax, and exclusions |
For a re-side, state how concealed damage will be handled. A separate repair allowance or an agreed change-order process is clearer than pretending you can inspect the sheathing through the old siding.
Compare what the warranties cover
LP explains its 5/50 limited warranty as five years of qualifying labor and material replacement, followed by prorated material coverage through the longer term. ExpertFinish has separate 15-year limited finish coverage. Hardie lists a 30-year non-prorated limited substrate warranty and 15-year limited ColorPlus finish coverage. LP warranty explanation, ExpertFinish product sheet, Hardie warranty overview
Fifty years versus thirty years isn't a complete comparison. Read the applicable warranty for proration, labor coverage, exclusions, transfer requirements, and the claim process. A finish warranty is different from substrate coverage, and neither tells you exactly when a house will need repainting.
For maintenance, follow the product's care instructions and inspect joints, coatings, clearances, and water drainage. Avoid a blanket promise that either siding will never need paint or maintenance.
Fire, moisture, and appearance
If a noncombustible cladding specification is driving the decision, Hardie's documented fiber-cement classification is a concrete reason to consider it. Noncombustible siding doesn't make a house fireproof. The complete wall assembly and the site's requirements still matter. Verify acceptance for the project before making a substitution. Hardie fire-performance documentation
For moisture, focus on installation details rather than a simple “waterproof” label. Follow each product's flashing, clearance, and finishing requirements. Neither choice excuses poor drainage or uncorrected leaks.
For appearance, compare full samples in daylight beside the proposed trim. Match texture, exposure, joint treatment, and finish sheen. Photos can help narrow the choice, but don't approve the color from a screen alone.
Our recommendation
Quote LP SmartSide when engineered wood is appropriate, the chosen profile and finish suit the customer, and its board lengths fit the layout and crew. Quote Hardie Plank when fiber cement meets the project's material requirements and your installation plan supports it. If both are suitable, present equivalent finished scopes and let the installed price, appearance, and documented differences decide.
Common questions
Does LP SmartSide last longer because its warranty is longer?
Warranty length isn't a service-life forecast. LP's prorated material coverage and Hardie's non-prorated substrate coverage work differently. Compare the terms and maintenance requirements, not just the headline years.
Is Hardie always more expensive to install?
No universal labor difference applies to every job. Crew experience, access, wall layout, board handling, cutting, and finish work determine the installation cost. Ask for those assumptions in the bid.
Can I compare a primed product with a factory-finished one?
Yes, if you include the complete finishing scope for the primed option. Otherwise, you're comparing unfinished material with a more complete package.