Ferndale Siding Two Different Materials, One Big Decision
Homeowners in Ferndale and around Whatcom County usually narrow their siding search down to two serious contenders: fiber cement and engineered wood, most commonly sold under the LP SmartSide brand. Both are a big step up from vinyl and both are marketed as low-maintenance, durable options. But they are not the same material, they do not behave the same way over twenty years of Pacific Northwest weather, and they are not interchangeable just because they sit next to each other in a showroom.
We install James Hardie fiber cement siding exclusively. We do not install LP SmartSide, and we want to explain why in plain terms, not sales language. Engineered wood is a legitimate product with real strengths. It also has a specific weakness that matters more here than almost anywhere else in the country: it is a wood-based product in a region that gets a lot of wet weather and holds moisture in the air for long stretches at a time.
What Engineered Wood Siding Gets Right
To be fair to the product, LP SmartSide has legitimate advantages that explain why it's popular:
- It's lighter than fiber cement, which can mean faster installation and lower labor cost on some jobs.
- It's easier to cut and nail without the specialized blades, dust control, and technique fiber cement requires.
- The strand-based engineered core resists the splitting and cupping problems that plague old-school solid wood siding.
- It comes pre-primed or pre-finished from the factory, which speeds up the finishing process.
- It carries a manufacturer warranty and, when it's installed correctly and maintained on schedule, it can perform well for years.
None of that is marketing spin. If you've seen SmartSide holding up fine on a house a few towns over, that's a real thing you saw. The issue isn't whether it can work. The issue is what it takes to keep it working, and how much room for error there is in a climate like ours.
Where Engineered Wood Struggles in Whatcom County
LP SmartSide is built from wood strands bonded with resin, then coated with a wax-based moisture-resistant treatment and a factory finish. That treatment is doing a lot of work, and it's doing it at the edges — cut ends, seams, fastener penetrations, corners — every place a saw or a nail touches the board in the field. Every one of those cuts needs to be sealed with the manufacturer's specified treatment, every time, by every crew member, for the life of the installation to hold up as designed.
Ferndale sits close enough to Bellingham Bay and the Strait of Georgia that salt-laden air is a regular part of the weather mix, on top of Whatcom County's long, wet fall-through-spring stretch and the moss season that follows it. Wood-based products absorb ambient moisture more readily than cement-based ones, and once water works its way past a compromised seal — at a cut edge, a poorly caulked joint, a spot where a fastener backed out slightly — the strand core can begin to swell, delaminate, or rot from the inside, often before it's visible from the outside.
That's not a defect unique to any one brand of engineered wood. It's the nature of a wood-composite product in a marine-influenced climate with high annual rainfall. It shifts the entire long-term performance of the siding onto two things a homeowner mostly can't control after installation day: how perfectly every field cut was sealed, and how consistently the caulking and touch-up gets maintained year after year.
What Fiber Cement Is and Why It's Different
Fiber cement siding is made from Portland cement, sand, and cellulose fibers, cured into a dense, rigid board. There is no wood grain to swell, no resin-bonded core to delaminate, and nothing in the material itself that rot fungus or moisture can feed on the way it can with a wood-based product. It doesn't mean fiber cement is indestructible or maintenance-free — it still needs to be installed with correct clearances, flashing, and caulking — but the underlying material doesn't have the same failure mode if a seal isn't perfect at every single cut.
Fiber cement is also non-combustible, which matters for insurance considerations and for wildfire-adjacent risk that's become more relevant across Washington in recent years. It holds paint and factory finishes with less expansion and contraction than wood-based siding, since it doesn't move as much with temperature and humidity swings.
James Hardie's HZ5 Engineering
James Hardie makes climate-specific product lines, and the HZ5 line is engineered for the Pacific Northwest's wet, moderate-temperature weather pattern rather than a generic national spec. That's a meaningful distinction — siding designed around the freeze-thaw cycles of the Midwest isn't necessarily optimized for a climate that's wet more often than it's cold.
Side-by-Side: The Real Trade-Offs
| Factor | Fiber Cement (James Hardie) | Engineered Wood (LP SmartSide) |
|---|---|---|
| Core material | Cement, sand, cellulose fiber | Wood strands with resin binder |
| Moisture behavior | Does not swell or rot; won't feed fungal growth | Vulnerable at unsealed cuts, seams, and fastener points |
| Combustibility | Non-combustible | Combustible (wood-based core) |
| Field-cut sensitivity | Low — cut edges are far less critical to long-term performance | High — every cut must be sealed correctly, every time |
| Typical maintenance | Periodic caulk/inspection; factory finish resists fading | Regular inspection of seals, caulk, and touch-up coating |
| Upfront material cost | Moderate to higher | Generally lower |
| Long-term cost risk | Lower — failure modes are rare when installed to spec | Higher if maintenance lapses or installation misses a detail |
| Warranty structure | Long-term, transferable manufacturer warranty | Manufacturer warranty, often with maintenance requirements to stay valid |
The Moisture Question, Specifically
This is worth slowing down on because it's the actual reason for our position, not a generic talking point. Whatcom County's weather pattern isn't defined by a few heavy storms — it's defined by long stretches of low-intensity rain, high humidity, and overcast days that don't give siding much chance to fully dry out between wet spells. Add the moss and algae growth that thrives in that same damp, shaded environment, especially on north-facing walls and under eaves, and you have a climate that tests a siding material's moisture tolerance almost continuously rather than in occasional extreme events.
A wood-based product can perform fine in a drier climate for decades with only routine upkeep. In a climate that stays damp for months at a stretch, the margin for a missed seal, a cracked caulk line, or a slightly under-driven fastener gets a lot smaller, and the consequences of that margin being crossed show up as rot rather than just cosmetic wear.
Installation Sensitivity Matters as Much as the Product
We'll say this plainly: a lot of siding problems blamed on "bad material" are actually installation problems. Engineered wood siding installed with every cut sealed, every fastener set correctly, and proper clearance from grade and hardscaping can perform well. The trouble is that standard is hard to guarantee across an entire job, across every crew member, on every single day of the install — and the homeowner has no way to verify it after the fact.
Fiber cement isn't immune to installation mistakes either. Improper flashing, insufficient clearance, or skipped caulking will cause problems with any siding material. But because the core material itself doesn't rot or swell, a fiber cement installation has more forgiveness built in when a detail isn't textbook-perfect. That's a meaningful difference when you're choosing what goes on your home for the next several decades.
Why We Standardized on James Hardie
We made the decision to install James Hardie exclusively because it lets us stand behind our work with confidence in this specific climate. We're not choosing it because it's the only decent product on the market — LP SmartSide has its place and performs reasonably well in drier regions. We're choosing it because Ferndale's combination of salt air, driving rain, and extended moss season rewards a material that doesn't depend on perfect, permanent sealing at every cut edge to avoid moisture damage.
Hardie's ColorPlus factory finish also means the color is baked on under controlled conditions rather than field-applied, which holds up more consistently against our fading and staining conditions than site-applied paint. And the warranty structure — a long-term, transferable warranty on both the product and, when installed by a certified contractor, aspects of the finish — reflects the manufacturer's own confidence in the material's durability.
What to Ask Any Siding Contractor
- What specific product line and climate zone rating are you specifying for my home?
- How do you handle flashing and clearance at grade, decks, and roof intersections?
- Is your crew factory-certified for the material you're installing?
- What does the warranty actually cover, and does it require documented maintenance to stay valid?
- Can you walk me through how cut edges and seams get treated during installation?
If you're weighing fiber cement against engineered wood for a home in Ferndale or anywhere in Whatcom County, we're happy to walk your property, talk through what we see, and give you a straightforward, no-pressure estimate — no hard sell, just an honest read on what your home needs.