Bellingham Siding What LP SmartSide Actually Is
LP SmartSide is an engineered wood siding product — strand board or oriented strand board (OSB) that's been treated with a zinc borate preservative and coated with resin, then finished with a primer or factory coating. It's a real step up from old untreated wood siding, and it has genuine advantages: it's lighter than fiber cement, easier to cut and nail without special blades, and generally less expensive per square foot installed. LP has also backed it with real engineering data and a lengthy warranty. We're not here to tell homeowners it's a bad product. We're here to explain why, after years of installing and repairing siding across Whatcom County, we made the call to stop putting it on homes.
The Core Issue: It's Still Wood
Underneath the treatment and the coating, LP SmartSide is wood fiber. Zinc borate protects against fungal decay and insects reasonably well as long as the factory-sealed edges and surfaces stay intact. The problem is what happens at the job site and afterward: every cut edge, every fastener penetration, every seam and butt joint is a place where that factory protection has to be re-established in the field with caulk, edge sealer, and paint. Miss one, or let caulk fail a few years down the road, and you've opened a path for moisture into a wood-based panel. Wood swells, delaminates, and rots from the inside — often before it shows on the surface.
That's a manageable risk in a dry climate with an installer who never cuts a corner. It's a much bigger risk here. Bellingham sits right on the water, and homes throughout Whatcom County deal with salt-laden air, driving rain off the Sound, and a long, damp moss season that keeps siding wet for months at a stretch. Engineered wood siding depends on every seal staying perfect, every year, for decades. That's a maintenance bet we're not willing to make on a customer's behalf.
Where We've Seen It Go Wrong
The failures we run into with LP SmartSide and similar engineered wood products aren't usually dramatic — they're slow. Common patterns include:
- Bottom-edge swelling near grade, decks, and downspouts where splashback keeps the lower courses wet longer than the rest of the wall.
- Caulk-dependent seams that need to be inspected and re-caulked on a schedule — skip a cycle and moisture gets a foothold before anyone notices.
- Fastener and cut-edge exposure where field crews didn't fully seal every trim cut, which is an easy step to shortcut when a job is moving fast.
- Moss and algae buildup in shaded, damp wall sections that holds moisture against the panel face longer than it should sit there.
None of this means LP SmartSide is defective. It means the product's long-term performance leans heavily on perfect installation and ongoing homeowner maintenance — inspecting seals, repainting on schedule, keeping vegetation and moss off the walls. In a marine climate like ours, that's asking a lot of a wood-fiber product over a 20-plus year ownership horizon.
Why We Standardized on James Hardie Instead
James Hardie fiber cement siding is made from sand, cement, and cellulose fiber — there's no wood core to swell, delaminate, or feed rot if a seal eventually gives out. It's non-combustible, which matters more every year as wildfire smoke and ember exposure become a regional concern even west of the Cascades. Hardie's HZ5 product line is engineered specifically for climates like ours, with freeze-thaw and moisture cycling built into the spec rather than left to field caulking.
The ColorPlus factory finish is also a big part of why we made this switch. It's baked on in a controlled facility rather than painted on-site, so the color and the protective topcoat go on before the siding ever sees rain, salt air, or a scaffold. That finish is backed by its own warranty separate from the substrate warranty, and it holds up to UV and coastal moisture far longer than field-applied paint typically does. For a house a few miles from the water in Bellingham, or tucked into a mossy, shaded lot inland, that difference in how the finish is applied and protected really does show up over a decade or two.
Our Standard, Plainly Stated
We install only James Hardie fiber cement siding. Not because every alternative is worthless, but because after years of tear-offs and repair calls in this climate, fiber cement is the one product we're comfortable standing behind for the long haul without hoping every seal holds. Homeowners deserve to know the trade-offs before they choose, not after the siding's been up for ten years.
| Factor | LP SmartSide | James Hardie Fiber Cement |
|---|---|---|
| Core material | Engineered wood (OSB/strand) | Cement, sand, cellulose fiber |
| Moisture vulnerability | Swells/delaminates if seals fail | Non-organic, does not rot |
| Finish | Field-primed or factory-primed, often field-painted | Factory-baked ColorPlus finish |
| Fire rating | Treated wood product | Non-combustible |
| Maintenance dependency | High — seals and paint need regular upkeep | Lower — finish and substrate are more stable |
If you're weighing siding options for a home in Bellingham or anywhere in Whatcom County, we're happy to walk through what we see on real jobs in this exact climate — no pressure, no sales script. Reach out for a free estimate and an honest conversation about what will actually hold up on your house.