Lynden Siding LP SmartSide Is a Real Product — Here's What It Gets Right
Before explaining why we don't install it, it's worth being straight about what LP SmartSide actually is. It's an engineered wood siding made from wood strands bonded with resin, treated with a zinc borate solution for insect and fungal resistance, and pressed under heat into panels or lap boards. It's lighter than fiber cement, easier on saw blades, and priced attractively compared to premium siding systems. For builders working on a budget in drier climates, it has a legitimate place in the market. We're not going to pretend otherwise.
Our reasons for not installing it in Lynden aren't about the product being defective. They're about matching a product's real-world behavior to the specific conditions homes face here in Whatcom County, and about the standard we've decided to hold ourselves to as a contractor who has to stand behind our work for decades, not just through the first paint cycle.
Lynden's Climate Is Genuinely Tough on Wood-Based Siding
Salt Air Off the Sound
Lynden sits inland from Bellingham Bay and the Salish Sea, and while we're not oceanfront, salt-laden air still moves through Whatcom County on prevailing westerly winds. Salt air accelerates the breakdown of fasteners, caulk joints, and factory finishes faster than it would in a landlocked climate. Any siding material that depends on an unbroken paint film or caulk seal to keep moisture out is more exposed here than the marketing materials assume.
Driving Rain, Not Just Rain
Whatcom County doesn't just get a lot of rainfall — a good share of it arrives sideways, driven by wind off the water and funneled through the Nooksack Valley. Wind-driven rain finds every gap, lap joint, and butt seam in a siding system and pushes water uphill against gravity. A siding product's tolerance for standing water at joints and cut edges matters more here than in a calm, dry climate.
A Long Moss and Shade Season
Between tree cover, cloud cover, and our long wet season, north-facing walls and shaded elevations in Lynden stay damp for extended stretches every year. That's exactly the environment where moss, algae, and mildew get a foothold on any siding surface, and where a substrate that can absorb moisture has the least chance to dry out between rain events.
The Core Issue: Wood Strand Substrate Meets Sustained Moisture
LP SmartSide's substrate is still fundamentally a wood product — strands of wood held together with resin, not a mineral-based material. Zinc borate treatment and a factory primer help resist rot and insects, but the underlying material still swells when it takes on water repeatedly, especially at cut edges, panel joints, and fastener penetrations where the factory treatment and finish aren't as complete as on the face of the panel.
In a drier climate with well-maintained paint and caulk, that's manageable. In a climate like Lynden's, where wet weather can stretch from October through May with short drying windows in between, any lapse in maintenance — a cracked caulk joint, a missed touch-up coat, a corner that got scraped during a move-in — becomes an entry point for moisture that the substrate underneath doesn't handle as gracefully as fiber cement does.
Edge Swelling Is the Tell
The most common early symptom on engineered wood siding in wet Pacific Northwest climates is edge swelling — a slight puffiness or roughness at cut ends and panel seams where moisture has been absorbed repeatedly. It's rarely dramatic at first, which is part of the problem: it's easy to miss during a routine walk-around until it's progressed enough that a section needs to be replaced rather than just re-caulked.
Installation Sensitivity We're Not Willing to Gamble On
Every siding product has an installation spec, and every spec matters. But some products have a wider margin for error than others, and LP SmartSide's long-term performance leans harder on getting every joint, gap, and caulk line right — on day one and every year after. That means:
- Every cut edge needs to be field-primed and sealed before installation, not just left to the factory coating on the face
- Panel and joint gaps need to be maintained exactly per spec so caulk doesn't have to bridge too wide a span
- Caulk joints need to be inspected and refreshed on a real maintenance schedule, not "whenever it looks bad"
- Flashing details at windows, doors, and butt joints need to be layered correctly since the substrate has less forgiveness for incidental water intrusion
None of that is unreasonable to ask of a contractor. But it does mean the long-term performance of the siding depends heavily on maintenance discipline from the homeowner for the life of the product — caulk and paint upkeep that, if skipped for even a couple of years in a climate like ours, can let moisture get ahead of the substrate's ability to dry out.
How the Maintenance Picture Compares
| Factor | LP SmartSide (engineered wood) | James Hardie (fiber cement) |
|---|---|---|
| Substrate | Wood strand, resin-bonded | Cement, sand, and cellulose fiber |
| Moisture absorption at cut edges/joints | Requires field priming and ongoing caulk maintenance | Non-combustible mineral substrate, far less prone to swelling |
| Repainting interval (unfinished/site-painted) | Typically every 5-8 years depending on exposure | ColorPlus factory finish rated well beyond that before repaint is needed |
| Fire resistance | Wood-based; treated but combustible | Non-combustible fiber cement |
| Insect/rot resistance | Borate-treated, effective if coating stays intact | Inorganic substrate, not a food source for insects or fungus |
| Typical manufacturer warranty structure | Prorated after initial full-coverage period | Long-term limited warranty, transferable to one subsequent owner |
The point of this comparison isn't to declare one product worthless. It's to show why, for a contractor installing siding meant to last through Whatcom County's wet cycles with minimal babysitting, fiber cement wins on the specific variables that matter most here: moisture behavior at the substrate level and how much ongoing maintenance the homeowner has to keep up with to protect that substrate.
Warranty Structure Is Part of the Decision
Warranty terms tell you a lot about how a manufacturer expects a product to age. Engineered wood siding warranties are commonly full coverage for a limited initial period and then shift to prorated coverage after that — meaning the manufacturer's own numbers assume some degree of wear that homeowners will absorb the cost of over time. James Hardie's fiber cement warranties are structured as long-term limited coverage and are transferable to one subsequent homeowner, which matters if you sell the home before you'd otherwise plan to reside it.
We install what we're willing to warranty our own labor against for decades, in this climate, without asking the homeowner to maintain a tight caulk-and-paint schedule just to keep the substrate protected.
Why We Standardized on James Hardie Instead
After years of seeing how different siding materials actually perform on Whatcom County homes — not in a brochure, but through wet winters, salt air, and shaded north walls — we made the call to install only James Hardie fiber cement. A few reasons that drove that decision:
- Non-combustible substrate — cement, sand, and cellulose fiber don't burn or feed insects and fungus the way wood-based products can
- Climate-engineered HZ product lines — Hardie makes region-specific formulations, and we install the versions engineered for wet, moderate coastal climates like ours
- ColorPlus factory finish — baked-on, backed by its own finish warranty, and far less dependent on the homeowner keeping up a repainting schedule
- Dimensional stability — fiber cement doesn't swell and shrink with moisture cycling the way wood strand products can at joints and cut edges
- A warranty structure we can stand behind — long-term, transferable, and consistent with how we want our name attached to a home for the next 20-plus years
Correct installation still matters with Hardie — flashing, fastener placement, and clearances all have to be done to spec. But the substrate itself gives us, and the homeowner, a lot more margin for error in a climate that doesn't offer many dry stretches to catch up on maintenance.
What to Ask Any Siding Contractor Before You Hire
Whatever material a contractor is proposing, a homeowner in Lynden should be asking pointed questions before signing a contract:
- What substrate is this product made from, and how does it handle sustained moisture exposure?
- Does this product require field-priming of cut edges, and is that included in the bid?
- What's the manufacturer's actual warranty language — full coverage or prorated, and for how long?
- Is the warranty transferable if I sell the house?
- What ongoing maintenance (caulking, repainting, inspection) does this product require to hit its expected lifespan?
- Has this contractor installed this specific product on homes in this climate, and for how long have those installations been in service?
A contractor who can answer those clearly, without dodging into generic marketing language, is one worth trusting with a decision this size.
Let's Talk About Your Home
Every home on your street, your lot's sun and shade exposure, and your budget are all different, and a siding decision should be made with those specifics in front of you, not just a general rule. If you'd like an honest, no-pressure look at what your home needs and what a James Hardie installation would actually involve, fill out the form below and we'll get you a free estimate.