Bellingham What LP SmartSide Actually Is
LP SmartSide is an engineered wood siding product. At its core it's strand-based wood — similar in concept to OSB sheathing — bonded with resins, then treated with a zinc borate additive (LP calls it SmartGuard) to resist fungal decay and insect damage, and finished with a proprietary coating. It comes in lap boards, panels, and trim, and it's manufactured to be lighter and easier to handle than fiber cement, with a lower material cost per square foot in most markets.
We get asked about it often enough that it's worth a straight answer: we don't install it, and this page explains why, without exaggerating anything about the product itself.
What LP Gets Right
Fair is fair. LP SmartSide has a real place in the siding market, and dismissing it outright wouldn't be honest.
- Workability: It cuts, nails, and handles more like traditional wood siding, which some crews find faster to install than fiber cement.
- Impact resistance: The engineered wood substrate flexes rather than cracking under a direct hit, which can matter in areas with hail or falling debris.
- Lower upfront material cost: It typically prices below fiber cement per square foot before labor and finish work.
- Decay treatment: The zinc borate treatment genuinely improves on untreated wood siding's resistance to rot and insects, when the coating stays intact.
Where it struggles is in exactly the conditions that define exterior siding here in Whatcom County — sustained moisture exposure over years, not just a single storm.
Why Our Climate Changes the Calculus
Bellingham sits where Puget Sound humidity, Pacific storm systems, and a long shoulder season of shade and dampness all overlap. Any siding product installed here has to hold up to three things at once: salt-laden air off the water, driving wind-driven rain that gets pushed sideways into wall assemblies, and a moss season that can stretch from fall through spring on north- and west-facing walls.
LP SmartSide is engineered wood. Wood-based products, even treated ones, share a fundamental vulnerability: if water gets past the surface coating and into the substrate, the strand board swells, and swelling doesn't reverse cleanly. Fiber cement doesn't have that failure mode — it's cement, sand, and cellulose fiber, and it doesn't swell or rot the way a wood-derived product can. In a drier inland climate, LP's coating and treatment may go a decade or more without ever being tested by sustained moisture. In Whatcom County, that test happens every winter.
The Salt Air Factor
Coastal and near-coastal properties around Bellingham Bay deal with airborne salt that accelerates coating breakdown on any painted or film-finished surface. Once a protective coating starts to chalk or thin, engineered wood siding loses its main line of defense faster than it would inland.
Driving Rain and Wall Assemblies
Wind-driven rain off the Sound doesn't just hit siding — it gets forced into laps, seams, and butt joints under pressure. Every field cut, every joint, and every fastener penetration on LP SmartSide is a spot where the factory treatment has been broken and needs to be resealed correctly by the installer. Miss one, and that's the point where moisture starts working its way in.
Moss Season
Shaded, damp siding grows moss and algae here in a way that drier climates rarely see. Moss holds moisture against the surface for months at a time. On a wood-based product, that's a much bigger long-term risk than it is on fiber cement, which doesn't feed the organic growth or absorb the moisture it holds.
Installation Sensitivity — Where Things Go Wrong
LP SmartSide isn't a bad product installed badly by bad crews everywhere; it's a product with a narrow tolerance for installation error, and that tolerance gets narrower in a wet climate. The manufacturer's own installation requirements reflect this:
- Every field-cut edge must be primed and sealed before the piece goes up — not after, not "when we get to it."
- Minimum ground clearance and proper flashing at every horizontal transition are non-negotiable, because standing water against the bottom edge is where swelling starts first.
- Caulking at butt joints and trim intersections has to be done with the right sealant and maintained over time — it's a wear item, not a one-time step.
- Paint and coating touch-ups on cut ends and fastener heads need to happen on a schedule, not "eventually."
Every one of those steps is doable. But it means the long-term performance of the siding depends on maintenance discipline continuing years after the crew that installed it has moved on to other jobs. We'd rather install a product where the material itself, not the maintenance calendar, is the primary line of defense against a Bellingham winter.
The Maintenance Burden Over Time
This is the part homeowners often don't hear about until they own the siding. LP SmartSide's warranty and long-term performance both depend on an ongoing maintenance routine: periodic repainting, recaulking of joints as sealant ages and shrinks, and prompt attention to any coating damage from impact, ladders, pressure washing, or age. Skip a cycle or two, and the exposed substrate underneath starts absorbing moisture in exactly the conditions Whatcom County produces most of the year.
Fiber cement has its own maintenance needs — it still needs to be painted and caulked — but the substrate underneath that paint isn't the thing failing if a maintenance cycle slips a year or two. That difference is the whole reason for our stance on this product.
Warranty Structure — Read the Fine Print
Engineered wood siding warranties, LP's included, are typically prorated and carry maintenance conditions: gaps in required upkeep, improper field-cutting, or missed sealing steps can limit or void coverage on the affected area. That's standard for the category, not unique to any one brand, but it means the warranty is only as strong as the maintenance paperwork behind it. A homeowner who can't produce records of repainting and recaulking on schedule may find a claim harder to support years down the road.
LP SmartSide vs. James Hardie Fiber Cement
| Factor | LP SmartSide (Engineered Wood) | James Hardie (Fiber Cement) |
|---|---|---|
| Core material | Wood strand substrate with resin binder | Cement, sand, and cellulose fiber |
| Moisture response | Can swell if coating is breached | Does not swell or rot |
| Combustibility | Combustible (wood-based) | Non-combustible |
| Coastal/salt air durability | Coating wears faster in salt exposure | ColorPlus factory finish holds up longer |
| Field-cut edge handling | Must be primed/sealed on-site every time | Less sensitive; still recommended but lower risk |
| Upfront material cost | Generally lower | Generally higher |
| Long-term maintenance dependency | High — coating integrity is critical | Lower — substrate itself resists moisture |
| Typical warranty structure | Prorated, maintenance-conditioned | Strong non-prorated, transferable options |
Why We Standardized on James Hardie Instead
We made a decision years ago to install one product line and install it well, rather than offer several products and spread our crews' expertise thin. James Hardie fiber cement is what we chose, for reasons that line up directly with what Bellingham's climate demands:
- Non-combustible core — cement-based siding doesn't burn, which matters in a region where wildfire smoke and ember exposure have become a bigger seasonal concern.
- Climate-engineered product lines — Hardie's HZ5 formulation is built specifically for regions with significant moisture exposure, which describes most of the Pacific Northwest.
- ColorPlus factory finish — a baked-on finish applied under controlled conditions holds color and resists fading and moisture intrusion better than field-applied paint on cut wood edges.
- Substrate that doesn't rot or swell — the material itself is the defense against moisture, not a maintenance schedule layered on top of it.
- Strong transferable warranty — coverage that's less dependent on proving a perfect maintenance history to a claims department.
Questions to Ask Before Choosing Any Engineered Wood Siding
If you're weighing LP SmartSide or a similar product against fiber cement for a home in Whatcom County, these are worth asking any contractor:
- Who is responsible for sealing every field-cut edge, and how is that documented?
- What's the realistic repainting/recaulking interval for this specific home's sun and shade exposure?
- What does the manufacturer's warranty actually require homeowners to prove if a claim comes up?
- How close is the siding to grade, and what's the flashing detail at every horizontal break?
- Has the installer worked with this exact product in a similarly wet, salt-air-exposed location before?
Our Bottom Line
LP SmartSide isn't a scam product or a poor choice everywhere — it performs reasonably well in drier climates with disciplined homeowners who keep up with maintenance. But we install siding for homes in Bellingham and across Whatcom County, where salt air, driving rain, and a long moss season stack the odds against any wood-based substrate over a 20- or 30-year horizon. We'd rather stand behind one product we trust completely than offer several and hope the maintenance holds up. That's why every siding job we take on goes out as James Hardie fiber cement.
If you're comparing siding options for a home in the Bellingham area, we're happy to walk through what we install and why — no pressure, no sales script. Reach out for a free estimate and we'll give you a straight answer about what your home actually needs.