LP SmartSide vs. James Hardie: How the Siding Options Compare

Q. We encountered LP SmartSide while comparing siding options. How does it compare with James Hardie fiber-cement siding?

The most familiar installation for both product families is lap siding installed as individual planks. Compared with vinyl, both can create the broad, straight courses people associate with painted wood siding, but they use different materials and installation methods.

James Hardie Fiber-Cement Siding

James Hardie lap siding is a fiber-cement product. The manufacturer describes its composition as sand, water, cellulose fibers, Portland cement, and proprietary additives. Cutting fiber cement can create respirable crystalline-silica dust, so current safety instructions and approved dust-control methods matter as much as the finished appearance.

LP SmartSide Engineered-Wood Siding

LP SmartSide is an engineered-wood product. LP's current literature describes precisely sized and layered wood strands protected through a process that includes industrial-grade resins, water-resistant waxes, zinc borate, and a resin-saturated overlay. It is not the same formulation as LP's earlier Inner-Seal product, whose history should not be used as a substitute for evaluating today's product documentation.

Board Lengths and Seams

The 2022 article compared 16-foot LP lap boards with 12-foot James Hardie planks, and those lengths remain listed for the current LP 38 Series lap profiles and HardiePlank HZ10 boards reviewed for this update. Longer boards can reduce the number of butt joints on uninterrupted runs, but a claim such as ‘33 percent fewer seams’ cannot be projected across a whole home: the result depends on profile, availability, openings, wall lengths, layout, waste, and the manufacturer's joint details.

Durability Depends on the Assembly

Material properties matter, but installed durability also depends on storage, clearances, flashing, fasteners, joint treatment, paint or factory finish, water management behind the cladding, and ongoing maintenance. Neither product is protected from poor detailing simply because it carries a recognized brand name.

How to Read the Warranties

LP's standard exterior warranty effective August 1, 2025 provides a 50-year substrate term. For a covered claim after installation, its stated remedy includes labor and material during years 1–5; during years 6–50 it covers material only, reduced by 2.22 percent per year. The warranty covers the original retail purchaser, original owner, and next owner—not later owners—and remains subject to its installation, maintenance, claim, remedy, exclusion, and arbitration terms. LP's separate Certified Installer program can extend the initial remedy from five to ten years when its eligibility and registration requirements are met; that is not the base warranty.

James Hardie's February 2024 HZ10 product warranty provides a 30-year, non-prorated term for covered products and extends to the first retail purchaser, first owner, and first transferee. Its substrate remedy does not pay labor or accessory-material costs. Hardie separately describes a 15-year ColorPlus finish warranty covering paint and labor against peeling, cracking, and chipping. These are different remedies with different conditions, so compare the legal documents for the exact product and finish rather than treating the headline year count as a verdict.

Installation and Safety

The two material systems require different handling and cutting methods. For outdoor power-saw cutting of fiber-cement board, James Hardie's current OSHA Table 1 summary calls for a handheld saw with a blade 8 inches or smaller, a commercially available dust-collection system operated to its instructions, and a filter rated at least 99 percent efficient. Other tasks or conditions can require a different compliance approach. Crew training, access, profile, trim, dust controls, wall geometry, and local labor all affect installation; neither system is automatically easier or less expensive on every house.

The Bottom Line

Both product families can create attractive, lower-maintenance exteriors when the wall assembly is designed well and trained installers follow the complete system requirements. Choose by comparing the exact profile, finish, warranty, maintenance expectations, installer experience, and water-management details—not by relying on one marketing claim.