Birch Bay LP SmartSide comes up in almost every siding conversation we have with homeowners in Birch Bay and up and down the Whatcom County coastline. It's a well-marketed product, it's less expensive than fiber cement in most bids, and a lot of contractors install it. We don't. This page explains what LP SmartSide actually is, where it performs fine, where it struggles in our specific climate, and why we standardized on James Hardie fiber cement instead. This isn't a takedown — it's the same conversation we have in person with homeowners who ask us why we won't quote it.
What LP SmartSide Actually Is
LP SmartSide is an engineered wood product. The core is strand board — wood fibers and strands bonded with resin under heat and pressure, similar in concept to OSB sheathing but manufactured with a proprietary process LP calls SmartGuard, which treats the strands with zinc borate and resin to resist moisture and insects. The exterior face gets a factory-applied primer or, on some lines, a resin-saturated overlay for extra weather resistance.
It's sold in lap siding, panel siding, and trim profiles, and it installs faster than cedar because it comes pre-primed and in long, consistent lengths. For a builder trying to hit a budget on new construction, it's a reasonable, well-engineered wood product. That's a fair statement, and we don't dispute it.
Where LP SmartSide Genuinely Gets It Right
- Cost: Typically runs less per square foot installed than fiber cement, which matters on tight budgets.
- Workability: Engineered wood cuts and nails like lumber, so installation crews familiar with wood siding pick it up quickly.
- Impact resistance: Reasonably tough against incidental impacts compared to vinyl.
- Warranty on paper: LP offers a manufacturer warranty that reads well, provided installation and maintenance requirements are followed to the letter.
If those four points were the whole story, we'd probably install it. They're not the whole story once you factor in what Birch Bay's climate does to a wood-based product over 15 to 25 years.
The Core Issue: It's Still Wood at the Cellular Level
Strip away the marketing and SmartGuard treatment, and LP SmartSide is still wood fiber. Wood fiber swells when it takes on moisture and shrinks when it dries out, and it's a food source for the fungi that cause rot and the algae that cause staining. The zinc borate treatment and resin binder slow that process down significantly compared to untreated wood — that's the entire point of the engineering — but they don't change the underlying material science. Every seam, every cut edge, every nail penetration is a place where the treated strand board is exposed and depends entirely on caulk, paint, and correct installation to stay sealed.
Fiber cement doesn't have that vulnerability. It's cement, sand, and cellulose fiber cured under pressure. It doesn't swell, it doesn't rot, and it isn't a food source for anything. That single material difference is the reason we standardized on Hardie rather than any wood-based product, engineered or not.
What This Means in Whatcom County Specifically
Birch Bay sits right on the water, which means salt-laden air moving across every exposed surface, driving rain off Georgia Strait that hits siding at an angle instead of just falling on it, and a wet season that stretches long enough to keep north- and shade-facing walls damp for weeks at a time. Add in the moss and algae that thrive in that kind of persistent moisture, and you've got a climate that stress-tests exactly the weak points engineered wood siding has: cut edges, seams, and any spot where the factory finish gets compromised.
None of that makes LP SmartSide fail outright. Plenty of installations hold up fine for years. But it does mean the margin for error on caulking, flashing, and field-cutting is thinner here than it would be in a dry inland climate, and the maintenance schedule to keep it performing is more demanding.
Installation Sensitivity Is the Real Trade-Off
Every field cut on LP SmartSide has to be primed or sealed before it goes up, every fastener penetration has to be treated correctly, and every seam and joint needs proper caulking maintained over the life of the product. Skip a step, or let caulk fail years later without recaulking, and moisture has a direct path into the strand board. Once that happens, the swelling and softening can progress under the paint film where you can't see it until the damage is well established.
We're not saying this to disparage the crews who install it well — plenty do. We're saying it because our own standard is to minimize the number of things that have to go exactly right, forever, for the siding to perform. Fiber cement is far more forgiving of a missed caulk line or a field cut that doesn't get fully sealed, simply because the base material isn't moisture-reactive to begin with.
Maintenance Burden Over the Life of the Siding
This is the part homeowners underestimate most. LP SmartSide, like any painted wood-based product, needs its paint film maintained — recaulked joints, touched-up cut edges, and repainting on a cycle, generally every 7 to 10 years depending on exposure, sooner on south- and west-facing walls that take direct sun and weather. Skip that maintenance and you're not just risking cosmetic fading; you're risking the moisture barrier that protects the strand board underneath.
James Hardie's ColorPlus finish is baked on at the factory with a warranty that typically runs 15 years against fading and peeling, and because the substrate underneath isn't moisture-reactive, a missed maintenance cycle doesn't carry the same risk to the material itself. For homeowners who want to set siding and mostly forget about it, that's a meaningful difference over two decades of Whatcom County weather.
Side-by-Side: What Actually Differs
| Factor | LP SmartSide | James Hardie Fiber Cement |
|---|---|---|
| Core material | Resin-treated engineered wood strand | Cement, sand, cellulose fiber |
| Moisture reaction | Can swell/soften if seals fail | Not moisture-reactive |
| Fire classification | Combustible (treated wood) | Non-combustible |
| Food source for fungus/algae | Yes, if moisture intrudes | No |
| Finish | Factory-primed or overlay; field-painted seams/cuts required | Factory ColorPlus finish, edge-to-edge |
| Maintenance cycle | Recaulk and repaint roughly every 7-10 years | Caulk inspection; repaint typically 15+ years out |
| Typical installed cost | Lower | Higher |
| Warranty structure | Conditional on installation/maintenance compliance | Strong transferable warranty on product and finish |
Fire and Insurance Considerations
Whatcom County isn't the wildfire-exposed terrain you'll find east of the Cascades, but fire classification still matters for insurance underwriting and, increasingly, for resale conversations as insurers scrutinize building materials more closely. Fiber cement is non-combustible. LP SmartSide, as an engineered wood product, is not — the treatments improve its fire performance versus untreated lumber, but it doesn't change its combustibility classification. For homeowners weighing insurance premiums or simply wanting the most conservative material choice, that's a straightforward, factual difference worth knowing.
Why We Standardized on James Hardie
We install one siding product because it lets us guarantee our work with confidence: James Hardie's HZ product lines are climate-engineered for exactly the kind of wet, marine-influenced weather Birch Bay sees — driving rain, salt air, and long stretches of damp shade. The ColorPlus factory finish removes the weakest link in most siding failures, which is field-applied paint that wasn't put on thick enough or cured long enough. And because fiber cement isn't a food source for the moss and algae that thrive in our moisture, it holds its appearance longer with less scrubbing and less repainting.
That's the whole case. We're not claiming LP SmartSide is a bad product — it's a legitimate engineered wood siding with real strengths. We're explaining why, given a choice, we've chosen to put only one material on the homes we're responsible for, and why that material is fiber cement rather than any wood-based option, engineered or otherwise.
A Practical Checklist If You're Comparing Siding Products
- Ask what the substrate actually is — wood-based, cement-based, or vinyl — and how each behaves when moisture gets behind it.
- Ask what the manufacturer warranty requires of you (maintenance schedule, caulking, repainting) to stay valid.
- Ask how the finish is applied — factory-cured versus field-applied — and how long it's rated to hold color and adhesion.
- Ask how the product performs in coastal, high-moisture climates specifically, not just its general national rating.
- Ask what ongoing maintenance the product needs over 10, 15, and 20 years, and price that into your decision, not just the install cost.
- Get the fire classification in writing if it affects your insurance.
Talk to Us Before You Decide
You don't have to take our word for any of this — ask questions, compare warranties side by side, and make the call that's right for your home and budget. If you want a straight, no-pressure look at what fiber cement would cost and look like on your house, we're happy to come take a look and walk you through it in person. Request a free estimate below and we'll give you honest numbers, not a sales pitch.