Bellingham Exterior Two Very Different Materials, One Common Question
Homeowners in Bellingham and across Whatcom County often ask us to compare James Hardie fiber cement with LP SmartSide engineered wood siding. Both are legitimate step-ups from vinyl, both are widely available through building supply yards in the area, and both get marketed heavily on durability and low maintenance. That said, they are made from fundamentally different materials, and those differences matter a lot once a product is facing our specific weather: salt-laden air off Bellingham Bay, long stretches of driving rain, and a moss season that can stretch from October through May in shaded, tree-covered lots.
This page lays out what each product actually is, how they perform under our conditions, and why our company made the decision years ago to install James Hardie exclusively. We are not going to tell you LP SmartSide is a bad product — it isn't. We are going to explain the trade-offs honestly so you can make an informed decision, whether you hire us or someone else.
What LP SmartSide Actually Is
LP SmartSide is an engineered wood product. Strands of wood are combined with resin and zinc borate (an insect and fungal treatment), then heat-and-pressure-formed into panels, trim, and lap siding, and finished with a treated outer layer. It is a real improvement over old-school composite hardboard siding that gave engineered wood a bad reputation in the 1990s, and LP backs it with a warranty that reflects genuine confidence in the product.
The core material, though, is still wood-based. That means its long-term performance depends heavily on keeping water out of the panel edges, keeping the factory or field-applied finish intact, and making sure caulking and flashing details are done correctly and stay that way for the life of the siding. Wood-strand products can perform very well for a long time when installation is precise and maintenance is kept up — but the margin for error is narrower than with a cementitious product, and that margin matters more here than it does in a drier climate.
What James Hardie Fiber Cement Actually Is
James Hardie siding is made from Portland cement, sand, and cellulose fiber, cured into a dense, rigid board. There is no wood strand or wood fiber structure to swell, and no organic resin matrix that can eventually break down under years of UV exposure and moisture cycling. It is factory-primed or, in most of what we install, finished with Hardie's ColorPlus baked-on coating, which is applied and cured in a controlled factory environment rather than sprayed on-site.
James Hardie also makes climate-specific product lines — including an HZ5 formulation engineered for regions with more moisture exposure, which the Pacific Northwest falls into. That is a meaningful detail for Whatcom County, where the product is being asked to perform in a wetter, cooler, more humid environment for most of the year than it would in, say, the Southwest.
How Each Holds Up to Bellingham's Moisture and Salt Air
The distinction that matters most locally is what happens when the material takes on water, either directly from driving rain or indirectly from humid, salt-tinged air sitting against the wall for days at a time.
| Factor | James Hardie Fiber Cement | LP SmartSide |
|---|---|---|
| Core material response to moisture | Cementitious core does not swell or rot; dimensionally stable | Wood-strand core can swell at compromised edges if water intrudes |
| Salt air / coastal exposure | Non-organic core is not vulnerable to salt-driven decay | Zinc borate treatment resists decay but relies on an intact wood structure |
| Finish durability | Factory-baked ColorPlus finish resists fading and cracking | Factory-treated finish performs well but is still applied over a wood substrate |
| Vulnerable points | Cut edges need field sealing; otherwise low sensitivity | Cut edges, butt joints, and panel seams are the highest-risk points for water entry |
Both products require correct edge sealing at cuts made on-site — that is not unique to either one. The difference is what happens if a seal eventually fails years down the road, which is common on any home given enough time, foot traffic near the wall, or a missed maintenance year. On fiber cement, a failed seal typically means localized staining that can be cleaned or repainted. On an engineered wood product, prolonged water intrusion at an unsealed edge or joint can allow the strand core to absorb moisture, and once that starts, it's a harder problem to reverse than it is on a non-organic board.
Moss, Algae, and the Maintenance Question
Anyone who has owned a home in Whatcom County for more than a season knows what moss and algae do to north-facing walls, shaded siding, and anything under a stand of Douglas fir or big-leaf maple. Both products can host surface growth — that's a function of shade, moisture, and lack of sun exposure, not the siding material itself. Where the products differ is what happens underneath that surface growth.
On fiber cement, sustained dampness from moss or algae sitting against the wall doesn't threaten the board's structural integrity — it's a cosmetic issue that a wash and, if needed, a fresh coat of paint resolves. On engineered wood, the same sustained dampness against an organic substrate is a more serious long-term concern, especially if it's happening at a seam, corner, or any spot where the factory treatment and finish aren't fully intact. In a region where moss season can run seven months out of the year, that's not a small distinction.
Fire Performance: A Real, Not Theoretical, Consideration
Fiber cement is non-combustible. Engineered wood siding, even with fire-retardant treatment, is still a wood-based product and carries a different fire classification than cement board. Wildfire risk gets most of the attention in this conversation, but house fires that start from an adjacent structure, a downspout fire, or an exterior ignition source are also part of the calculation. For us, this is one of the clearest, least debatable reasons to standardize on a non-combustible exterior — it's not a matter of opinion, it's a difference in the material itself.
Installation Sensitivity — Both Are Installer-Dependent
Neither of these products performs to its potential with a sloppy installation. Both require correct fastener placement, proper clearance from grade and hardscape, correct flashing at windows, doors, and penetrations, and properly sealed cut edges. This is true across the industry — most siding failures we get called out to inspect, on any brand, trace back to installation shortcuts rather than a defective product.
Where the two diverge is in the consequences of a mistake. A fastener driven wrong or a joint left unsealed on fiber cement tends to show up as a cosmetic issue that's fixable. The same mistake on an engineered wood product interacts with an organic core, and the failure mode can progress further before it's caught. That's part of why we've made fiber cement, installed to Hardie's published fastening and clearance specifications, our standard — it gives less room for a small installation error to become a bigger structural one.
Warranty Structure
| James Hardie | LP SmartSide | |
|---|---|---|
| Manufacturer warranty type | Long-term, non-prorated coverage on the core substrate; ColorPlus finish carries its own coverage | Manufacturer warranty covering the substrate and treatment |
| Transferability | Transferable to a subsequent homeowner, which matters for resale | Check current terms — transferability and proration schedules vary by product generation |
| What voids it | Typically installation outside Hardie's published specs | Typically installation, finishing, or maintenance outside LP's published requirements |
Warranty terms change over time on any manufacturer's product line, so we always tell homeowners to read the current published warranty directly rather than relying on general reputation. What we can say from an installer's standpoint is that Hardie's warranty structure and its transferability were part of what made it the easier product to stand behind for the life of a home, not just the life of the original owner.
Cost Factors to Weigh
- Material cost: LP SmartSide typically has a lower material cost per square foot than James Hardie fiber cement.
- Installed cost: The gap narrows once labor, trim, and finish work are factored in, since both require skilled installation.
- Repaint/refinish cycle: ColorPlus factory finish is designed to go longer between repaints than field-applied or standard factory finishes.
- Long-term maintenance: Factor in the cost of periodic washing, caulk inspection, and any repainting over a 20-30 year ownership horizon, not just the install-day price.
- Resale consideration: A transferable warranty and non-combustible material can be a talking point when a home eventually goes on the market.
Why We Standardized on James Hardie
We don't install LP SmartSide, vinyl, or other engineered or wood-based siding products. That's a deliberate standard, not a lack of familiarity with the alternatives. Given what our climate does to exterior materials — driving rain off the Sound, salt air, and moss season that keeps walls damp and shaded for months — we decided we'd rather build our reputation on a non-combustible, dimensionally stable material with a factory-cured finish and a transferable warranty than split our crews' expertise across multiple systems with different installation requirements and different long-term risk profiles.
That's the honest reasoning. LP SmartSide is a legitimate product with real engineering behind it, and plenty of homes wear it well when it's installed and maintained correctly. We simply concluded that fiber cement was the better long-term bet for Bellingham homes, and we built our business around installing it correctly rather than installing several products adequately.
Questions to Ask Before You Choose a Siding Contractor
- Ask what specific product line and HZ climate zone rating they're proposing for your home.
- Ask to see their fastening schedule and clearance details in writing, not just verbally described.
- Ask how they handle cut-edge sealing on-site, since this is the single biggest failure point on any lap siding.
- Ask whether the manufacturer warranty is transferable and what voids it.
- Ask how they detail siding at grade, decks, and roof lines — these are the spots where Bellingham's rain finds its way in.
If you're weighing siding options for a home in Bellingham or elsewhere in Whatcom County, we're happy to walk your property, point out what your current siding is telling us, and give you a straight answer on what we'd recommend and why. Reach out for a free, no-pressure estimate using the form below.