Bellingham Siding Two Engineered Sidings, One Big Difference
If you're replacing siding in Bellingham, two products keep coming up: James Hardie fiber cement and LP SmartSide. Both are marketed as upgrades over vinyl and both are engineered wood-adjacent products designed to outperform old-school cedar and plywood siding. But they're built from fundamentally different materials, and that difference matters a lot in a place like Whatcom County, where salt air off Bellingham Bay, driving winter rain, and a moss season that can run six months out of the year all work against a home's exterior.
We only install James Hardie. Not because LP SmartSide is a scam or a bad product in every application — it isn't — but because after weighing how each material handles our specific climate, we standardized on the one we trust to hold up here with less risk to the homeowner.
What LP SmartSide Actually Is
LP SmartSide is an engineered wood product: strand board made from wood fibers, resins, and waxes, treated with a zinc borate preservative and coated with a resin-saturated overlay for weather resistance. It's lighter than fiber cement, easier to cut and nail without special blades, and generally less expensive installed. For dry climates or homes where budget is the primary driver, it has real advantages.
The trade-off is that it's still wood at its core. Wood, treated or not, expands, contracts, and is vulnerable to moisture intrusion at cut edges, fastener penetrations, and seams if the factory coating is ever compromised — by a hairline crack, a missed caulk joint, or years of UV and moisture cycling. In a climate that stays wet from October through May, with morning dew and marine fog adding to the moisture load even on days it isn't technically raining, that vulnerability doesn't stay theoretical for long. Once moisture gets behind the treated shell, wood-based siding can swell, delaminate at the edges, or invite rot in ways that are hard to catch early because the damage starts under the surface.
What James Hardie Is Built From
James Hardie siding is fiber cement — cellulose fiber, sand, and portland cement, cured into a dense, stable board. There's no wood fiber to swell, no organic material for moss and mildew to feed on the way they do on cedar or wood-composite siding. It's also non-combustible, which matters for insurance and for peace of mind given how many structure fires start at exterior siding and eaves.
Hardie's HZ5 product line, which is what we specify for Pacific Northwest installs, is climate-engineered for regions with sustained moisture exposure. The factory-applied ColorPlus finish is baked on under controlled conditions, which gives more consistent, longer-lasting color adhesion than field-applied paint on wood siding — important on the north- and west-facing walls of Bellingham homes that take the brunt of wind-driven rain off the Salish Sea.
Side-by-Side: What Actually Matters
| Factor | LP SmartSide | James Hardie |
|---|---|---|
| Core material | Engineered wood strand | Fiber cement (no wood) |
| Moisture behavior | Resistant when coating is intact; vulnerable if breached | Doesn't swell, rot, or delaminate from moisture |
| Combustibility | Combustible (wood-based) | Non-combustible |
| Moss/mildew susceptibility | Low to moderate — organic surface | Very low — no organic food source |
| Finish | Factory overlay + field paint over time | Factory-baked ColorPlus, longer color life |
| Weight/installation | Lighter, faster to install | Heavier, requires fiber-cement-rated tools and technique |
| Typical upfront cost | Generally lower | Generally higher |
Where LP SmartSide Makes Sense — and Why We Still Don't Install It
We'll say it plainly: LP SmartSide is a legitimate product, and in drier regions or on budget-driven projects it performs reasonably well when installed and maintained correctly. But "installed and maintained correctly" is doing a lot of work in that sentence, especially somewhere like Bellingham. Every seam, cut end, and fastener hole is a potential entry point for moisture, and our marine climate doesn't give those weak points much of a break between rain events. We'd rather stand behind one material we know performs consistently in this specific environment than sell two products with different risk profiles and different long-term outcomes.
That's also why installation quality matters as much as the product choice. Fiber cement siding installed with the wrong fastener pattern, insufficient clearance from grade, or poor flashing detail can still fail early — the material only performs to spec when the install matches Hardie's published guidelines. We follow those specs on every job, not as an upsell, but because it's the difference between siding that lasts and siding that doesn't.
The Bottom Line for Whatcom County Homes
Both products can look great on day one. The real test is what they look like in year twelve, after a decade of Bellingham winters, salt-laden air, and moss trying to take hold on every north-facing surface. We've made our call: James Hardie fiber cement, installed to spec, with a transferable warranty behind it. If you're weighing your options and want a straight answer about what will actually hold up on your home, we're happy to walk the property with you and give you a free, no-pressure estimate.