Lynden Exterior Homeowners researching new siding for a home in Whatcom County almost always run into the same two finalists: James Hardie fiber cement and engineered wood products like LP SmartSide. Both are marketed as upgrades over vinyl and both look good on a sample board in a showroom. But they are fundamentally different materials with different long-term behavior, and after years of installing and repairing siding in this climate, we made a deliberate choice about which one goes on the homes we work on. This page explains that choice honestly, including what engineered wood does well.
What Engineered Wood Siding Actually Is
Engineered wood siding is manufactured from wood strands or fibers bonded with resins under heat and pressure, then coated with a resin-saturated overlay and factory finish designed to resist moisture better than raw wood. It's a real improvement over old-school cedar and primed spruce in terms of consistency and impact resistance. It's lighter than fiber cement, easier on installers' saw blades, and generally less expensive per square foot installed.
The core material is still wood-based. That's the entire story of this comparison — everything else follows from that one fact.
Where It Performs Well
- Lighter weight makes it faster to install and easier to handle on tall walls or gable ends
- Impact resistance is generally good — it doesn't chip the way fiber cement can if struck hard
- Lower material cost than fiber cement in most markets
- Available in lap, panel, and trim profiles similar to fiber cement
Why Wood-Based Siding Struggles in Our Climate
Lynden sits in a stretch of Whatcom County that gets driving rain off the Georgia Strait and Puget Sound weather systems, long stretches of damp fall and winter weather, and a moss season that can run six months or more depending on the year. Add proximity to salt air along the coastal edges of the county, and you have a climate that tests any wood-based product's weakest point: the cut edges and any place the factory coating gets compromised.
Engineered wood siding relies entirely on its factory coating and correct field sealing of every cut, joint, and fastener penetration to keep moisture out of the wood substrate. Miss one cut end, one nail that wasn't sealed per spec, or one caulk joint that fails a few years down the road, and water gets into the wood fiber. Once that happens, the same resin bonding that makes the product strong also means it swells, delaminates, or breaks down from the inside — often before it's visible from the outside.
The Maintenance Reality
Manufacturers of engineered wood products are explicit that field-cut edges must be primed or sealed before installation and that caulking at joints needs to be inspected and maintained over the life of the product. That's not a one-time task — it's an ongoing maintenance obligation for the homeowner, in a region where moss and algae growth accelerate any breakdown in the protective coating. Skip a few years of upkeep and the risk of moisture intrusion climbs.
What Fiber Cement Is Made Of — and Why That Matters
James Hardie fiber cement is cellulose fiber, sand, and portland cement pressed and cured into a rigid board. There's no wood fiber in the substrate to absorb water, swell, or rot. It won't feed moss the way a wood-based surface can, and it's non-combustible — a real consideration for any homeowner thinking about wildfire-adjacent insurance requirements or simple peace of mind.
Hardie also engineers specific product lines for different climate zones. The HZ5 line used in our region is formulated for cold, wet climates rather than being a one-size-fits-all product. That's a meaningful difference from a generic national product line — it means the plank composition itself accounts for the freeze-thaw cycles and sustained moisture exposure that define a Whatcom County winter.
ColorPlus Factory Finish
Most Hardie installations we do use ColorPlus, a factory-applied finish baked on under controlled conditions rather than field-painted. It carries its own finish warranty separate from the substrate warranty, and it resists the fading and chalking that field-applied paint shows first, especially on south and west-facing walls that take the brunt of UV exposure between rain events.
Side-by-Side: The Factors That Actually Matter
| Factor | Engineered Wood (e.g. LP SmartSide) | James Hardie Fiber Cement |
|---|---|---|
| Core material | Wood strand/fiber with resin binder | Cement, sand, cellulose fiber — no wood |
| Moisture behavior | Depends on intact coating and sealed cuts | Substrate does not swell or rot from moisture |
| Fire rating | Combustible, treated for ignition resistance | Non-combustible |
| Moss/algae resistance | Wood-based surface can support growth if coating degrades | Cement surface is inherently less hospitable |
| Ongoing maintenance | Cut-edge sealing and caulk inspection required | Caulk maintenance still required, but no wood substrate at risk |
| Climate-specific engineering | Generally one national formulation | Regional HZ product lines (e.g. HZ5 for our climate) |
| Installed cost | Typically lower material cost | Higher material cost, offset by longevity |
| Weight | Lighter, faster to handle | Heavier, requires correct fastening technique |
Why We Standardized on One Product
We used to get asked to bid both products side by side, and for a while we installed whatever the homeowner chose. Over time, the callbacks and repair calls told us something the marketing brochures didn't: the failures we saw in this climate were disproportionately on wood-based products, and they traced back almost every time to a coating breach — an unsealed cut end, a failed caulk joint, a fastener that let water track into the substrate. That's not a knock on any specific brand's engineering; it's the physics of a wood-based product living in a place that stays wet for months at a time.
Rather than install two different products and give two different sets of maintenance advice, we made a call: we install James Hardie fiber cement, exclusively. It lets us guarantee our installation practices are dialed in for one system, our crews are deeply experienced with Hardie's fastening and flashing requirements, and we can stand behind the work without hedging.
Installation Is Where Warranties Actually Get Decided
Both product categories have installation-sensitive warranties — meaning improper installation can void manufacturer coverage regardless of which product you choose. The difference is what a mistake costs you. A caulking or flashing error on engineered wood risks the wood substrate itself. The same error on fiber cement risks moisture at the joint, but the board underneath isn't going to swell or rot. That gap in downside risk is a big part of why we chose the side we did.
What Correct Hardie Installation Looks Like
- Proper starter strip and minimum ground clearance to keep splash-back off the bottom course
- Correct fastener type, spacing, and penetration depth per the Hardie fastening schedule for our wind zone
- Field-cut edges primed before installation, per manufacturer spec
- Rain screen or drainage plane behind the siding where the wall assembly calls for it
- Proper flashing and kick-out details at every roof-to-wall intersection and window head
- Correct joint gaps and sealant compatible with ColorPlus finish
Any of these done wrong will cause problems eventually, on any siding product. This is as much about who's on your roof and ladders as it is about which brand of board they're carrying up.
Cost Over the Life of the Siding
Engineered wood typically costs less installed, which is a legitimate reason some homeowners choose it, especially on a budget-driven remodel or an investment property. Fiber cement costs more upfront. Where that gap tends to close is over a 20-30 year ownership horizon: less repainting, less risk of substrate damage from a missed maintenance cycle, and a transferable warranty that matters if you sell the home. We won't tell you engineered wood is a bad product — we'll tell you why we personally stopped installing it, and let you weigh the trade-off with real numbers from your own estimate.
Making the Right Call for Your Home
If you're comparing bids and one contractor is pushing engineered wood hard on price alone, ask directly how they handle cut-edge sealing, what their caulk maintenance recommendation is, and whether they'll put installation details in writing. If you're comparing a Hardie bid, ask the same questions — the answers should be more straightforward because there's no wood substrate at stake.
We're happy to walk you through both products on your specific home, including where your walls face prevailing weather and how much sun and moss exposure different elevations get. If you'd like a straightforward look at what fiber cement siding would cost and involve for your property, we offer a free, no-pressure estimate — just fill out the form below.