Bellingham Siding LP SmartSide comes up in almost every siding conversation we have with Bellingham homeowners, usually because a neighbor has it, a builder recommended it, or it showed up cheaper on an online quote. It's a legitimate product with real engineering behind it, and we're not going to pretend otherwise. But we made a decision years ago to install only James Hardie fiber cement on the homes we work on, and SmartSide is one of the products we walk away from. Here's the honest reasoning, not a sales pitch dressed up as a "buyer's guide."
What LP SmartSide Actually Is
SmartSide is an engineered wood product — strand-based OSB (oriented strand board) panels or lap boards, treated with a resin-and-zinc borate formula and coated with a wax layer, then primed at the factory. LP has improved the product significantly since the OSB siding failures of the 1990s that led to a major class-action settlement. The current SmartSide line (branded "Trim & Siding") is a different manufacturing process than that older product, and it carries a real warranty. We want to be clear about that up front: this is not the same material that caused problems decades ago, and it's unfair to homeowners to imply otherwise.
What SmartSide gets right:
- It's lighter than fiber cement, which can mean faster installation and lower labor cost on paper
- It holds paint well when properly maintained and can be cut with standard wood-working tools
- It's typically less expensive per square foot than fiber cement siding, both material and install
- It performs reasonably well in dry, moderate climates when detailing is done correctly
The Core Problem: It's Still Wood
Underneath the resin treatment and factory primer, SmartSide is wood fiber. Wood swells, wicks moisture, and eventually breaks down when water gets past the surface — that's just the nature of the material, not a manufacturing defect. The entire performance of the product depends on the coating and the caulking staying intact at every seam, every cut edge, and every fastener penetration for the life of the siding. In a dry climate, that's a manageable risk. In Bellingham and the rest of Whatcom County, it's a much harder bet.
What Our Climate Does to That Bet
We get sustained fall and winter rain, a marine layer that keeps humidity high for weeks at a stretch, and salt air rolling in off Bellingham Bay and the Sound that accelerates the breakdown of coatings and fasteners. Add in a long moss and algae season on north-facing walls and anything shaded by evergreens, and you have a climate that is constantly testing the weak points of an engineered wood product — the field cuts, the butt joints, the corners, and any spot where caulk shrinks or a gutter overflows onto a wall. Any cut edge on a job site has to be field-sealed with the correct primer before installation, every time, or that edge becomes the entry point for water. That's a lot to ask of an install crew on a rainy jobsite in November, and it's the single biggest reason we don't take on SmartSide work.
Where the Failures Actually Start
We're not going to make unverified claims about SmartSide failing broadly — we haven't run controlled studies, and neither has anyone else making noise on either side of this debate online. What we can speak to, from years of working on homes in this county, is where engineered wood siding problems tend to originate when they do happen:
- Field-cut edges that weren't primed and sealed before installation
- Butt joints and seams where caulk has shrunk, cracked, or was never installed with the right gap and backer rod
- Ground contact or low clearance, where splash-back keeps the bottom edge of a board wet for days after a storm
- Behind gutters or downspouts that overflow during our heavier winter storms and soak the same section of wall repeatedly
- Shaded, moss-prone walls where organic growth holds moisture against the surface far longer than a sun-exposed wall
Every one of those is a workmanship or maintenance variable, not necessarily a product flaw. But that's exactly the point — SmartSide's real-world performance is only as good as the installer's attention to every seam, and its long-term look is only as good as the homeowner's willingness to keep up with caulk inspections, repainting, and gutter maintenance. That's a heavier ongoing commitment than most homeowners realize when they're comparing sticker prices.
Maintenance Burden: The Part That Gets Glossed Over
Every siding product needs some maintenance. The difference is in what happens if you fall behind. With SmartSide, a few years of deferred caulking or a repaint that gets pushed back can let moisture start working into the substrate before it's visible from the ground. By the time you can see swelling, delamination, or soft spots at the bottom of a board, the damage has usually been progressing for a while underneath the paint film. Fiber cement doesn't eliminate maintenance — you still need to keep it caulked and painted — but the substrate itself doesn't break down the same way when a maintenance cycle gets delayed a season or two, which matters in a climate where storm season doesn't always leave a convenient window for exterior work.
How the Two Products Actually Compare
| Factor | LP SmartSide | James Hardie Fiber Cement |
|---|---|---|
| Core material | Engineered wood strand (OSB-based) | Cement, sand, and cellulose fiber |
| Moisture behavior | Resistant when coating is intact; vulnerable at cut edges and breaches | Non-organic; doesn't swell, rot, or feed moss the way wood does |
| Combustibility | Combustible (wood-based) | Non-combustible |
| Finish options | Factory primed; field paint required | ColorPlus factory finish available, or primed for field paint |
| Typical upfront cost | Lower | Higher |
| Sensitivity to install detailing | High — every cut edge and seam matters | Moderate — still needs correct flashing and gapping, less coating-dependent |
| Warranty structure | Manufacturer warranty, often prorated after early years | Long-term manufacturer warranty; ColorPlus finish warranty separate |
Why We Standardized on Hardie Instead
We stopped installing several products over the years — not just SmartSide — because we got tired of being the crew called back to explain damage that traced to a product's inherent weak points rather than our workmanship. Fiber cement solves the core issue for our climate: it's not organic material, so it doesn't feed moss, doesn't swell at a damaged edge the way wood fiber does, and doesn't rely entirely on an unbroken coating to keep water out of the substrate. It's also non-combustible, which matters more each year as wildfire smoke seasons stretch further north into Washington.
James Hardie's HZ10 product line is specifically engineered for climates like ours — cold, wet, and humid for long stretches — rather than a one-size-fits-all national spec. The ColorPlus factory finish also takes the weakest link (field-applied paint) mostly out of the equation, since the color is baked on at the factory with a warranty attached to the finish itself. That doesn't mean Hardie is maintenance-free or foolproof if installed poorly — it absolutely still requires correct flashing, gapping, and caulking at trim details. But the failure mode we see most often with engineered wood siding in this climate — moisture entering at a compromised edge and doing slow damage from within — is much less of a risk with a cement-based product.
What to Ask Before You Choose Either Product
Whatever siding you're considering, these are the questions worth asking any contractor before signing anything:
- Will every field cut be primed and sealed on-site before it goes on the wall, or only the factory edges?
- What's the manufacturer's actual warranty language — is it prorated, and what voids it?
- How does this product perform specifically in a wet, marine climate — not just a national average?
- What ongoing maintenance (caulk inspection, repainting cycle, gutter checks) does this product require to hit its expected lifespan?
- Is the installer certified or specifically trained on this product's detailing requirements?
- What happens at ground clearance, deck ledger connections, and other high-moisture-exposure points?
The Bottom Line
LP SmartSide isn't a scam product, and plenty of homes around Western Washington carry it without major issues, especially where installation was meticulous and maintenance stayed current. But we install siding for a living in a county with salt air, long wet winters, and a moss season that doesn't let up, and we'd rather turn down a job than install a product whose long-term performance here depends on flawless field detailing and a homeowner never falling behind on caulk and paint. James Hardie fiber cement lines up better with what Bellingham weather actually does to a house over twenty or thirty years, which is why it's the only siding we put our name behind.
If you're weighing options for your home, we're happy to walk the property with you, look at your specific exposure — sun, shade, wind direction, moisture patterns — and give you a straight answer about what will actually hold up. Reach out for a free, no-pressure estimate.