Bellingham Exterior Two Different Materials, One Big Decision
If you're replacing siding in Bellingham, you've probably run into two products marketed as the "modern" alternative to cedar: James Hardie fiber cement and LP SmartSide engineered wood. They get compared constantly because they're priced in a similar range and both promise to outperform old-fashioned wood siding. But they are fundamentally different materials, and that difference matters a lot once you factor in Whatcom County's climate.
We install James Hardie exclusively. We don't install LP SmartSide, vinyl, or any wood-based siding product. Here's the honest reasoning behind that, and what each material actually is.
What LP SmartSide Actually Is
LP SmartSide is an engineered wood product — wood strands and fibers bonded with resins, then coated with a wax-based moisture barrier called SmartGuard, and finished with primer at the factory. It's a real improvement over old solid-wood siding: it resists fungal decay better than untreated cedar, it's more dimensionally stable, and it costs less upfront than fiber cement in most markets.
The trade-off is what it's still made of at its core: wood. Wood strands, no matter how they're engineered and sealed, remain vulnerable to moisture intrusion if the factory coating is ever compromised — through a cut edge left unsealed, a fastener hole, a caulk joint that fails, or years of driving rain finding a seam. Once moisture gets past that outer barrier, the wood substrate can swell, delaminate, or begin to break down. That failure mode is invisible until it isn't.
Why Whatcom County's Climate Raises the Stakes
This isn't a hypothetical concern here. Bellingham sits in a marine climate with salt air off Bellingham Bay, long stretches of driving rain most of the year, and a moss season that can run from fall through spring on north-facing walls and shaded lots. That combination is tough on any wood-based product:
- Salt air accelerates the breakdown of coatings and fasteners over time, giving moisture more opportunities to find a way in.
- Driving rain, especially wind-driven rain off the water, pushes water into laps, seams, and cut edges harder than a calm, dry climate would.
- Extended moss and mildew season keeps organic material sitting against the siding surface for months, holding moisture close to the wall assembly instead of letting it dry out.
Engineered wood siding can perform well for years in this environment when it's installed and maintained perfectly — factory edges sealed, cut edges field-treated, caulking inspected annually, gutters and flashing kept in good repair. The problem is that "perfectly" is a high bar to hold for 20-30 years across every homeowner, every installer, and every re-caulking cycle.
Why We Standardized on James Hardie
James Hardie siding is fiber cement — a mix of cement, sand, and cellulose fibers, with no wood substrate to swell, rot, or delaminate if moisture reaches it. That single difference removes the failure mode that engineered wood products are structurally built around managing.
A few specifics that matter for our climate:
- Non-combustible material — fiber cement doesn't burn, which isn't a climate-driving-rain issue but is a real difference from any wood-based product.
- HZ5 engineered product line — Hardie makes climate-specific formulations, and the HZ5 line is engineered for wet, freeze-prone regions like the Pacific Northwest, with moisture and impact resistance suited to what we actually experience here.
- ColorPlus factory finish — a baked-on finish applied under controlled conditions, which holds up better against fading and moisture than field-applied paint or primer, and reduces (though doesn't eliminate) the repainting cycle homeowners face with wood-based siding.
- Won't rot or support pest damage the way a wood substrate can if water gets behind the finish.
What Fiber Cement Doesn't Solve
To be fair, James Hardie isn't maintenance-free and it isn't magic. It's heavier and more brittle than engineered wood, which means installation quality matters enormously — improper fastening, wrong nail placement, or skipped flashing details can cause problems regardless of the material. It still needs proper caulking at joints and periodic inspection like any siding product. And it costs more upfront than LP SmartSide in most cases. We think that cost difference buys you a materially lower-risk product for a climate like ours, but it's a real trade-off worth knowing going in.
The Warranty Difference
James Hardie backs its products with a strong, transferable limited warranty — a meaningful factor if you plan to sell the home down the road, since it can pass to the next owner rather than resetting or voiding at sale. Warranty terms and coverage specifics vary by product line, so we'll walk through exactly what applies to your project when we scope the job.
Our Bottom Line
LP SmartSide is a legitimate, better-than-old-wood product, and plenty of contractors install it successfully. We simply made a professional judgment call: in a Bellingham climate with salt air, sustained rain, and a long moss season, we'd rather put our name behind a material that doesn't depend on a coating staying perfectly intact for decades. That's why James Hardie fiber cement is the only siding system we install.
If you're weighing your options for a siding replacement in Bellingham or elsewhere in Whatcom County, we're happy to walk your home, look at your exposure and existing siding condition, and give you a straight answer on what makes sense. Reach out for a free, no-pressure estimate using the form below.