Lynden What LP SmartSide Actually Is
LP SmartSide is an engineered wood siding product. The core is strand-based wood (similar in concept to OSB), pressed and bonded with resins, then treated with a zinc borate solution to resist fungal decay and insects, and finished with a proprietary coating system. It's a real improvement over the untreated hardboard siding that gave engineered wood a bad name in the 1990s, and it has a loyal following among builders who like its workability — it cuts, nails, and finishes a lot like real wood, at a lower material cost than fiber cement.
We're not going to tell you LP SmartSide is a bad product. In the right climate, installed exactly to spec, it holds up reasonably well. Our decision not to install it isn't about the manufacturer — it's about what we've chosen as our standard for homes in Whatcom County, and why.
The Core Issue: It's Still a Wood Product
Zinc borate treatment and factory coatings slow down moisture damage, but they don't change the fundamental nature of the substrate. LP SmartSide is wood fiber. Wood fiber swells when it stays wet and shrinks when it dries. Every cut edge, every fastener penetration, and every seam is a place where that treated core can be exposed if the coating isn't maintained perfectly — caulked, painted, and re-sealed on a schedule, forever.
That's a manageable trade-off in a dry climate. It's a much bigger ask in Lynden. Whatcom County doesn't get brief rain events — it gets months of low-intensity, wind-driven rain that keeps siding wet for days at a stretch, followed by a moss season that runs long into what other parts of the country would call spring. Add the salt-laden air that moves inland off the Salish Sea and Birch Bay, and you've got a combination that's hard on any exterior material, but especially hard on one where the water-resistance depends on an intact factory coating and diligent caulk maintenance.
Installation Sensitivity
LP SmartSide's warranty is conditional on installation details that are easy to get right on paper and easy to get wrong in the field:
- Minimum clearance from grade, roof lines, and decks — measured in inches that matter
- Every field cut re-sealed with the correct primer/sealant before the piece goes up
- Caulk joints at every butt seam, corner, and penetration, inspected and refreshed over the life of the siding
- Proper flashing and drainage plane behind the siding so incidental moisture has somewhere to go
None of this is exotic — it's just unforgiving. Miss a step, or let maintenance lapse for a few years (which happens on real houses owned by busy people), and moisture finds the one seam or fastener hole where the treatment wasn't fully protecting the wood underneath. By the time it shows on the surface, the damage is often already inside the wall.
The Warranty Structure
LP's warranty is real, but like most engineered wood products, its coverage is tied tightly to documented, correct installation and ongoing maintenance — caulking schedules, repainting intervals, and so on. That puts a lot of the long-term performance burden on the homeowner, years after the installer has moved on. We didn't want to sell a product where "the warranty is only as good as your caulk gun discipline" is the honest answer to how it holds up.
Why We Install James Hardie Instead
We standardized on James Hardie fiber cement for every home we side, full stop. A few reasons that matter specifically for this climate:
- The core material isn't wood. Hardie's fiber cement is cement, sand, and cellulose fiber. It doesn't rot, it doesn't feed insects, and it doesn't swell the way wood-based products can when it stays wet — which, in a Lynden winter, it will.
- ColorPlus factory finish. The color coat is baked on at the factory under controlled conditions, not applied on site or touched up with field paint. That's a more consistent, longer-lasting bond than a job-site coating schedule can reliably deliver.
- Climate-engineered product lines. Hardie makes region-specific HZ formulations built around exactly this kind of wet, marine-influenced climate, rather than a one-size-fits-all national spec.
- A stronger, more straightforward warranty. Hardie's transferable warranty terms aren't contingent on a homeowner maintaining a caulk-and-repaint schedule to keep coverage valid.
Fiber cement isn't magic — it still needs to be installed correctly, with proper flashing, clearances, and sealed joints, same as anything else. The difference is what happens if maintenance slips for a season or two, which is realistic for most homeowners. Fiber cement's failure mode is gradual and forgiving. An engineered wood product's failure mode, once moisture gets past the coating, is not.
Our Honest Bottom Line
If a contractor installs LP SmartSide correctly and a homeowner keeps up with caulking and repainting, it can perform acceptably in a lot of climates. We just don't think that's a fair bet to make on a house in Whatcom County, where driving rain, prolonged dampness, moss growth, and salt air are the norm rather than the exception. We'd rather put one product on every home — installed the same careful way every time — than manage two different maintenance conversations depending on what's on the wall.
If you're weighing siding options for a home in Lynden or anywhere else in Whatcom County, we're happy to walk through what we install and why, with no pressure to sign anything. Reach out for a free estimate and we'll give you a straight answer about what your house actually needs.