Sudden Valley Siding LP SmartSide comes up in almost every siding conversation we have in Sudden Valley, and for good reason — it's a well-known product, it's less expensive than fiber cement, and it looks decent going up. We get asked to install it regularly, and we turn that work down. Not because the product is a scam or because we're trying to upsell anyone, but because after years of working on homes around Lake Whatcom and throughout Whatcom County, we've settled on one siding system we trust completely: James Hardie fiber cement. Here's the honest reasoning behind that decision.
What LP SmartSide Actually Is
LP SmartSide is an engineered wood product — strand board (OSB) that's treated with zinc borate for insect and fungal resistance, then coated with a resin-saturated overlay and primed at the factory. It's a real step up from the old untreated hardboard siding that gave engineered wood a bad name in the 1990s. LP has put real engineering into the substrate treatment, and for a lot of climates, it performs reasonably well when it's installed and maintained correctly.
The trade-off is baked into the material itself: it's still wood. Wood expands, contracts, and — if moisture gets past the surface — swells and deteriorates from the inside out. That's the core issue we weigh against our climate here.
Why That Matters in Sudden Valley Specifically
Sudden Valley sits right on Lake Whatcom, and the broader Whatcom County climate isn't gentle on exterior building materials. We get a long, wet moss season that can stretch from fall through spring, driving rain that comes in sideways off the water during winter storms, and enough proximity to the Puget Sound corridor that salt-laden air is a real factor on siding, fasteners, and trim. Any product with a wood-based substrate depends entirely on its factory coating and field-applied caulking staying intact to keep water out. In this climate, that margin for error is thin.
Any cut edge, nail penetration, or seam that isn't caulked and maintained on schedule becomes a place where moisture can start working into the strand board. Once that happens with an OSB-based product, the damage isn't cosmetic — it's structural swelling that doesn't reverse.
Where LP SmartSide Falls Short for Our Standards
- Maintenance dependency: Field-cut edges, seams, and any spot where the factory coating is compromised need to be sealed and re-sealed as part of ongoing upkeep. Miss a maintenance cycle in a wet climate like ours and the risk compounds.
- Moisture behavior: Because the core is engineered wood, moisture intrusion leads to swelling, checking, and eventual rot rather than the material simply shrugging off exposure the way a mineral-based product does.
- Installation sensitivity: Getting the clearances, flashing, and caulking right on every cut edge and joint is non-negotiable with this product. There's very little room for a rushed install or a skipped step to go unnoticed.
- Warranty structure: LP's warranties on SmartSide are generally prorated after an initial period, meaning the coverage you have on year one isn't the coverage you have on year fifteen.
None of this means LP SmartSide is a bad product in the abstract — plenty of homes around the country wear it well. It means that for our specific climate, and for the standard we hold our installs to, we don't think it's the right long-term bet for homeowners who are paying for siding once and expecting it to last.
Why We Install James Hardie Instead
James Hardie fiber cement solves the core problem for us: it isn't wood, so it isn't subject to the same moisture-driven swelling and rot pathway. It's a non-combustible, cement-and-cellulose composite that holds its shape and finish in wet, salt-influenced, moss-prone conditions far more predictably.
A few specifics that matter to us as installers:
| Factor | Why it matters here |
|---|---|
| ColorPlus factory finish | Baked-on finish resists fading and chipping better than field-applied paint, which matters when a house faces years of driving rain and damp winters |
| HZ5 climate-engineered formulation | Hardie's HZ product lines are engineered for specific moisture exposure zones, which lines up with the wet Pacific Northwest reality we're building for |
| Non-combustible core | Removes an entire category of risk that a wood-based substrate can't fully escape |
| Transferable warranty | Coverage that holds its value if the home changes hands, which matters for resale in a market like Whatcom County |
We're not going to tell a homeowner that every LP SmartSide install in the region has failed — that wouldn't be honest, and it isn't true. What we can say is that when we looked at the moisture exposure our homes actually see — the moss season, the driving rain off the lake and the Sound, the salt air — we decided we didn't want to be the contractor whose install depends on a homeowner keeping up a strict caulking and maintenance schedule for decades to avoid rot. That's a real trade-off, and it's the reason we standardized on fiber cement instead.
The Bottom Line
If you're comparing siding materials for a home in Sudden Valley or anywhere else in Whatcom County, it's worth understanding what you're actually choosing between: a treated engineered-wood product that performs well with diligent upkeep, versus a fiber cement product engineered specifically for wet, coastal-influenced climates with less ongoing maintenance burden. We made our choice based on what we've seen hold up here over time, not based on what's cheapest to install.
If you'd like to talk through your specific home, its exposure, and what siding actually makes sense for it, we're happy to walk the property with you and give you a straight answer. Reach out for a free, no-pressure estimate — there's no obligation, and we'll tell you honestly what we'd recommend for your situation.