Lynden Exterior What LP SmartSide Actually Is
LP SmartSide is an engineered wood siding product — strand board or wood fiber saturated with resin, pressed into panels or lap boards, and coated with a wax-based moisture treatment called SmartGuard. It's manufactured by Louisiana-Pacific, sold nationwide, and installed on a lot of homes because it's lighter than fiber cement, easier for some crews to cut and nail, and generally cheaper per square foot up front. None of that is a knock on the product. It has a legitimate place in the market, especially in drier climates where the wood substrate isn't fighting standing moisture year-round.
We get asked about it often enough that it's worth a straight answer: we don't install it. Not because it's a scam or because every LP SmartSide job fails — plenty don't. It's because after weighing how it performs specifically here in Whatcom County against what we're willing to put our name behind, we standardized on one product line instead. This page explains the reasoning so you can make your own informed call, whichever contractor you end up hiring.
What LP SmartSide Gets Right
Credit where it's due:
- Workability — it cuts, nails, and handles more like traditional wood siding, which some crews find faster to install than fiber cement.
- Weight — lighter panels mean less strain during installation and slightly lower shipping and handling costs.
- Price point — material cost is typically lower than fiber cement, which matters on tight budgets.
- Appearance — factory-primed boards take paint well and can mimic traditional wood lap or panel styles convincingly.
If you live somewhere dry, with wide roof overhangs, good gutters, and a contractor who follows LP's installation and caulking specs to the letter, SmartSide can hold up reasonably well. The trouble is that "somewhere dry" doesn't describe Lynden.
The Core Issue: It's Still Wood
Underneath the resin treatment and factory coating, LP SmartSide is a wood-based product. Wood-based siding has one job it has to win at every single day it's on your house: keeping bulk water out of the substrate. As long as the wax-impregnated coating and every seam, cut edge, and fastener penetration stays sealed, the product performs. The moment water finds a way in — through a hairline gap in caulking, a field cut that wasn't re-sealed, a nail that backed out, or a joint where two panels meet — the wood fiber core is exposed to exactly what it's most vulnerable to: swelling, softening, and eventually rot.
This isn't a hypothetical failure mode. It's the same failure mode every engineered wood and OSB-based siding product has wrestled with for decades, and it's why manufacturers put so much emphasis on strict installation details — minimum ground clearance, exact caulking requirements at every joint, sealing every field-cut edge, specific nail placement. The product's long-term performance depends heavily on the installer executing every one of those details correctly, every time, on every board. Skip one, and that's where the problem starts — usually a few years down the road, after the crew is long gone.
Why That Matters More in a Marine Climate
Lynden sits inland from Bellingham Bay and the Salish Sea, close enough that homes here regularly deal with salt-laden air on top of the Pacific Northwest's baseline moisture load. Salt air accelerates the breakdown of caulking and sealants faster than it does further inland — the same joints that need to stay perfectly sealed on a wood-based siding product are under more chemical stress here than in, say, eastern Washington. Add Whatcom County's driving rain, which comes in sideways off frequent winter storms rather than falling straight down, and you get wind-driven moisture pushed directly into lap joints and butt seams — exactly the spots where engineered wood siding is most dependent on flawless sealing.
Then there's moss. Lynden's long wet season, shaded lots, and mild year-round temperatures create ideal conditions for moss and algae growth on north-facing walls and anywhere airflow is limited. Moss holds moisture against the siding surface for extended periods — it doesn't just sit there looking bad, it keeps the substrate wet longer than open exposure would. On a fiber cement product, that's a cosmetic and cleaning issue. On a wood-fiber product, prolonged surface moisture next to a compromised seal is the exact scenario that leads to swelling and delamination at panel edges.
Installation Sensitivity Isn't a Small Detail
Every siding product has an installation spec. The difference with engineered wood is how unforgiving the margin for error is. Fiber cement, by contrast, doesn't rely on an unbroken moisture seal to protect its core — the material itself doesn't swell or rot the way wood fiber does, even if a joint isn't perfectly caulked. That gives fiber cement a wider margin of safety when real-world installation conditions aren't textbook-perfect, which matters because most job sites, including ours, aren't textbook-perfect. Crews deal with weather delays, mid-project changes, and dozens of small field decisions. We'd rather stand behind a product that tolerates normal variability in installation than one that requires flawless execution on every seam to perform as advertised for 20-plus years.
Warranty Structure: Read the Fine Print
Engineered wood siding warranties are typically prorated — full coverage for a short initial period, then declining coverage over the following years, and they commonly exclude moisture-related failure if installation or maintenance requirements weren't followed to spec. That last part is the catch: if a claim comes down to whether every caulk joint was maintained correctly for a decade, the burden of proof often lands on the homeowner. Fiber cement warranties from established manufacturers are generally structured differently — non-prorated for a longer stretch and less dependent on ongoing homeowner maintenance of sealant joints to stay valid. When you're choosing a product that will be on your house for the next few decades, the warranty structure is worth reading in full before you sign anything, not just the headline "25-year" or "50-year" number on the brochure.
Side-by-Side: What We're Actually Comparing
| Factor | LP SmartSide (Engineered Wood) | James Hardie (Fiber Cement) |
|---|---|---|
| Core material | Resin-treated wood strand/fiber | Cement, sand, cellulose fiber |
| Combustibility | Combustible | Non-combustible |
| Moisture tolerance | Depends on unbroken seal at every joint | Doesn't swell or rot if seal fails locally |
| Performance in salt air / driving rain | Sealant and coating under more stress | Substrate unaffected by moisture exposure |
| Moss/algae exposure | Prolonged surface moisture is higher risk | Cosmetic concern, not a structural one |
| Factory finish | Primed, needs field paint typically | ColorPlus baked-on finish available, no field paint needed |
| Installation margin for error | Narrow — spec must be followed exactly | Wider — more forgiving of field conditions |
| Material cost | Generally lower | Generally higher |
Neither column is "wrong" in every situation. In a dry climate with meticulous, code-perfect installation, the SmartSide column looks a lot more competitive. In Lynden's climate, the risk profile shifts enough that we decided we weren't comfortable installing it and standing behind it for the long haul.
Why We Standardized on James Hardie Instead
Fiber cement solves the core problem directly: it's not made of wood, so it doesn't rely on a perfect, permanent seal to avoid swelling or rot. James Hardie's HZ5 product line is specifically engineered for climates like ours — colder, wetter, with more freeze-thaw cycling than the HZ10 line built for hot, humid regions. That's not marketing language; it's a real difference in the formulation and it's why we spec HZ5 on every Lynden install. Add a factory-baked ColorPlus finish, which removes field painting and the ongoing maintenance that comes with it, a non-combustible core, and a warranty structure that isn't hinging on decade after decade of flawless caulk maintenance, and it's a product we can install once and not worry about revisiting in five years because a seam let go.
We're not saying every home in Whatcom County needs fiber cement, or that every SmartSide installation is doomed. We're saying that when we weighed the honest trade-offs against the climate we actually work in — salt air off the Salish Sea, sideways winter rain, and a moss season that runs most of the year — we picked the product with the wider margin for error and put our name behind it exclusively.
Questions Worth Asking Before You Choose a Siding Product
- What is the core material, and how does it behave if a seam or joint fails years from now?
- Is the warranty prorated, and does it require documented ongoing maintenance to stay valid?
- Is this specific product line engineered for a cold, wet climate, or a general nationwide spec?
- What ground clearance, flashing, and caulking details does the manufacturer require — and will the crew actually follow them?
- Does the finish require field painting, and who's responsible for repainting down the road?
- Has the contractor installed this product in this climate before, and can they explain why they chose it?
Get a Straight Answer for Your Home
Every house on your street has a different exposure — some get hammered by wind-driven rain off open fields, others sit shaded and damp under trees where moss takes over fast. We'll walk your property, look at your specific exposure, and give you a straightforward assessment of what your siding actually needs, not a sales pitch. If you'd like a free, no-pressure estimate on a James Hardie installation, reach out and we'll get you scheduled.