Sudden Valley Siding Two Products That Look Nearly Identical on a Spec Sheet
If you've spent any time researching fiber cement siding, you've probably come across both James Hardie and Cemplank. On paper, they're close cousins. Both are Portland cement, sand, and cellulose fiber composites. Both come in lap siding, panel, and trim profiles. Both are non-combustible and resist rot, insects, and woodpeckers in ways that vinyl and wood products simply can't. A homeowner comparing spec sheets side by side could reasonably wonder why a contractor would pick one over the other.
We get asked about this often enough that it's worth laying out plainly. We install James Hardie products exclusively — we don't quote, stock, or install Cemplank. That's not a marketing preference. It's the result of years of installing fiber cement siding on homes throughout Whatcom County, watching how different products age under our specific weather, and deciding we'd rather stand behind one system we know inside and out than split our expertise, warranty support, and inventory across two similar-but-not-identical products.
What Cemplank Gets Right
Fairness first: Cemplank, manufactured by Plycem, is a legitimate fiber cement product, not a knockoff. It has real advantages over vinyl siding and untreated wood — it won't melt against a hot grill, it holds paint far longer than wood siding, and it's not a food source for carpenter ants or woodpeckers. For a homeowner on a tighter budget who still wants the core benefits of fiber cement over vinyl or wood, Cemplank is a reasonable product in the right hands with the right installer.
Where our concerns come in isn't the raw material chemistry — it's the manufacturing consistency, the factory finish system, the regional engineering, and the warranty and dealer support structure behind the product once it's on your wall in a marine climate like ours.
Manufacturing Consistency
James Hardie has run dedicated fiber cement plants in North America for decades and is by far the largest producer in the category, which shows up in board-to-board consistency — thickness, density, and moisture content stay tight from batch to batch. Cemplank, as a smaller-volume player, has historically shown more run-to-run variation in our experience ordering and handling it. Small inconsistencies in density or moisture content don't always show up on install day. They show up two or three winters later, as slightly different expansion behavior between boards on the same wall.
Why Regional Climate Changes the Calculus
Fiber cement siding doesn't fail the same way in every climate, and this is really the heart of why we make the call we do. Sudden Valley sits on Lake Whatcom in Whatcom County, and homes here deal with a specific combination of stresses: salt-laden air moving in off the Puget Sound and Georgia Strait corridor, long stretches of driving rain off the water, and a moss and algae season that can run eight or nine months out of the year on north- and west-facing walls. None of that is dramatic on its own, but it's relentless, and relentless is what wears out a marginal factory finish or a marginal caulk joint.
James Hardie engineers its HZ5 product line specifically for this kind of climate zone — colder, wetter Pacific Northwest conditions — with a formulation tuned for moisture cycling and freeze-thaw behavior. Cemplank does not offer the same degree of published, climate-zone-specific engineering. That gap matters less in a dry climate and matters quite a bit here, where siding spends much of the year at high moisture saturation.
Factory Finish: The Part That Actually Determines How Your Siding Looks in Year 10
The single biggest real-world difference between these two products isn't the substrate — it's the finish system baked onto it at the factory, because that finish is what's actually exposed to sun, rain, and salt air every day.
| Factor | James Hardie (ColorPlus) | Cemplank |
|---|---|---|
| Finish application | Baked-on factory finish, multiple coats cured under controlled conditions | Factory-primed; topcoat is typically field-applied or a separate painted line |
| Color consistency | Matched across full job, touch-up product sold to match | More dependent on field painting quality and timing |
| Fade/chalk resistance | Backed by a dedicated finish warranty | Dependent on paint product and applicator, not manufacturer-backed the same way |
| Caulk/touch-up needs | Lower, factory-matched touch-up available | Higher reliance on field caulking and repainting cycles |
A factory-cured finish cures far more evenly and durably than anything applied on a jobsite or a paint line under variable weather. In a climate where siding is wet more often than it's dry, an inferior or inconsistent finish is exactly where you'll see problems first — chalking, fading, and hairline cracking at seams that let moisture behind the board.
Warranty Structure: Read the Fine Print, Not Just the Headline Number
Both companies advertise warranty coverage, and both numbers can look similar on a sales sheet. What differs is how transferable, well-documented, and widely supported that warranty is in practice.
- James Hardie: Non-prorated substrate warranty plus a separate ColorPlus finish warranty, transferable to a subsequent homeowner under standard terms, backed by a manufacturer with decades of claims history and a large national network of Elite/Preferred contractors familiar with the process.
- Cemplank: Offers its own warranty coverage, but with a smaller installer and dealer network nationally, and less of a track record we can point to locally when a homeowner asks "what happens if something goes wrong in year twelve."
A warranty is only as useful as the ecosystem behind it. We'd rather tell a homeowner in Sudden Valley exactly how a Hardie claim gets handled, because we've done it, than sell a product where that answer is more theoretical.
Installation Sensitivity: Where Most Fiber Cement Failures Actually Start
Here's something both manufacturers would agree on: most fiber cement siding failures — on either brand — trace back to installation, not the board itself. Improper fastening, missed clearances, wrong caulk, and skipped flashing details cause the overwhelming majority of callbacks in this trade. That said, product-specific installation guides and fastener requirements differ, and running two parallel systems means a crew has to hold two sets of specs in their head at once. We'd rather our crews be deeply, repeatably expert in one system's requirements than reasonably competent in two.
- Minimum ground and roof clearances specific to the product line
- Correct fastener type, length, and spacing for the substrate and exposure
- Proper joint treatment and flashing at every butt seam
- Manufacturer-specified gap and caulk product at trim transitions
- Field-cut edge sealing before installation, not after
- Correct nailing pattern for high-wind and high-moisture exposure zones
Get any one of those wrong and it doesn't matter which brand of fiber cement is on the wall — moisture will find its way behind it eventually. That's exactly why the installer matters as much as the product, and why we chose to build our entire installation process around a single, well-documented system.
The Business Reason, Said Plainly
There's also a practical side to this we won't dress up. Stocking, warranting, and training on two competing fiber cement lines means splitting attention, splitting inventory, and splitting our relationship with manufacturer support between two companies instead of building deep expertise with one. James Hardie's Elite Preferred contractor programs give us direct manufacturer training, warranty backing, and technical support that we can pass straight through to homeowners. We didn't find an equivalent depth of program with Cemplank that we felt confident standing behind for a home that has to survive Whatcom County winters for the next thirty-plus years.
What We Install Instead, and Why
We install James Hardie's HZ5 climate-engineered products with ColorPlus factory finish on every fiber cement project we take on. It's non-combustible, it's warranted with a company and a local dealer network we can vouch for directly, and it's formulated for exactly the moisture cycling, salt exposure, and moss-prone conditions that define this part of the county. When a product line is engineered for our climate zone specifically — rather than being a general-purpose fiber cement board sold everywhere from Arizona to Maine — that shows up in how the siding looks and performs a decade in, not just on install day.
None of this means Cemplank is a bad product in the abstract. It means we made a deliberate choice about what we're willing to put our name behind on homes that have to hold up to driving coastal rain and a moss season that doesn't quit. If you're weighing fiber cement options for your own home, we're happy to walk through what we've seen, what the warranty differences actually mean in practice, and why we landed where we did.
If you'd like to talk through your siding options for a home in Sudden Valley or elsewhere in Whatcom County, reach out for a free, no-pressure estimate. We'll walk your home, look at your exposure, and give you a straight answer — no obligation.