Bellingham Two Different Materials, One Long Wet Season
Homeowners in Bellingham and across Whatcom County usually narrow their siding search down to two finalists: James Hardie fiber cement and LP SmartSide engineered wood. Both are marketed as upgrades over vinyl. Both look good on a sample board in a showroom. But they are fundamentally different materials, and after years of installing and repairing siding in this climate, we made a deliberate choice to carry only one of them. This page explains the reasoning honestly, including what engineered wood does well, so you can make sense of the decision rather than just take our word for it.
What LP SmartSide Actually Is
LP SmartSide is an engineered wood product: wood strands bonded with resins, then coated with a wax and zinc borate treatment for moisture and insect resistance, and finished with a primer coat. It's lighter than fiber cement, easier to cut and nail without special blades, and it has a real following among builders because it installs faster and costs less upfront. For dry inland climates, or homes with generous roof overhangs and good gutter maintenance, plenty of SmartSide installations perform fine for years.
The catch is in the name: it is still wood at its core. Wood strand product resists moisture better than solid lumber, but it does not stop being organic material. Its long-term performance depends heavily on an unbroken paint film and correct field caulking at every joint, seam, and penetration. Once that film is breached and water gets past it, the strand core can swell, delaminate, or soften, and that damage isn't always visible from the outside until it's advanced.
Why That Matters Specifically Here
Bellingham sits right on Bellingham Bay, which means salt-laden air is a constant, not an occasional event. Add in the driving rain that comes off the Sound in fall and winter storms, and a moss season that can run from October well into spring on north-facing walls and shaded lots, and you have a climate that tests every weak point in a siding system relentlessly. Salt air accelerates the breakdown of paint films and fasteners. Wind-driven rain forces water sideways into seams and laps that would stay dry in a calmer climate. And moss holds moisture against the wall surface for months at a time, right where an engineered wood product is most vulnerable — at the paint line and the cut edges.
None of this means SmartSide is a bad product everywhere. It means the margin for error shrinks a lot in a marine climate like Whatcom County's, and the maintenance burden goes up. Field-cut edges need to be sealed correctly every time, caulking needs to be inspected and refreshed on a schedule, and gutters and flashing details have to be right and stay right. That's a lot of ongoing responsibility to put on a homeowner for a product whose core material is still moisture-sensitive.
Why We Standardized on James Hardie
James Hardie fiber cement is made from cellulose fiber, sand, and Portland cement, pressed and cured into planks and panels. It contains no wood strand core to swell or delaminate, and it's non-combustible — a real consideration during dry summer stretches when wildfire smoke and ember risk become regional news even west of the Cascades. Hardie also engineers specific product lines (its HZ5 formulation, for example) for climates like ours, accounting for moisture exposure rather than treating the Pacific Northwest the same as a dry Southwest install.
The factory-applied ColorPlus finish is the other half of the decision. Instead of a primer coat that still depends on correct field painting, ColorPlus is baked on in a controlled factory process and backed by its own finish warranty, separate from the substrate warranty on the siding itself. That combination — a cement-based core that doesn't feed on moisture, plus a finish that isn't riding on how well the paint holds up on a rainy jobsite — is what convinced us to stop offering engineered wood options and install fiber cement exclusively.
Side-by-Side, Plainly
| Factor | LP SmartSide (engineered wood) | James Hardie (fiber cement) |
|---|---|---|
| Core material | Wood strand, resin-bonded | Cement, sand, cellulose fiber |
| Combustibility | Combustible | Non-combustible |
| Finish | Primed; field or shop painting typical | Factory-baked ColorPlus finish available |
| Moisture behavior | Resistant, not immune; edge sealing critical | Does not swell or delaminate from moisture |
| Maintenance load | Higher — caulk and paint film upkeep | Lower — mainly cleaning and caulk inspection |
What Correct Installation Still Requires
Choosing Hardie isn't a substitute for good workmanship. Fiber cement still needs proper flashing, correct nailing patterns and clearances, sealed cut edges, and rainscreen or drainage detailing appropriate to a coastal, high-rainfall site. A poorly installed Hardie job and a well-installed one age very differently, especially with the moss and driving rain this area sees every winter. That's why installation quality matters as much as material choice, and it's the other half of what we control on every job.
If you're weighing siding options for a Whatcom County home and want a straight answer about what will actually hold up here, we're happy to take a look and walk through it in person. Reach out for a free, no-pressure estimate — no obligation, just an honest read on your home's exposure and what it needs.