Semiahmoo Siding Two Different Ways to Solve the Same Problem
Homeowners in Semiahmoo and across Whatcom County have two serious siding materials to choose between once they've ruled out vinyl and bare wood: fiber cement and engineered wood, sold under brand names like LP SmartSide. Both are marketed as durable, paintable, and built to hold up better than old-growth cedar or plain plywood siding. They are not the same product, though, and they don't respond to our climate the same way. We install James Hardie fiber cement exclusively, and we think homeowners deserve a straight explanation of why.
What Engineered Wood Gets Right
LP SmartSide and similar engineered wood products are strand-based panels bonded with resins and coated with a treated overlay, then primed at the factory. They're lighter than fiber cement, easier for a crew to cut and nail, and less taxing on tools and backs during installation. The upfront material cost is usually lower than fiber cement, and for a lot of the country, especially drier climates, these products perform reasonably well for their expected service life. We're not going to pretend otherwise.
Why Engineered Wood Is a Harder Sell Here
The problem isn't the factory panel — it's what happens to that panel once it's on a house that sits fifteen minutes from the water, wrapped in salt air, driving rain, and a moss season that can run eight or nine months out of the year. Engineered wood is still wood at its core. Wood swells, wicks, and eventually breaks down when it stays wet, and the treated resin coating is a barrier, not a permanent seal. Every fastener hole, cut edge, and butt joint is a place where moisture can start working its way in, and once it does, the strand board underneath doesn't dry out and recover the way a solid material would.
That matters more here than almost anywhere else in Washington. Semiahmoo's exposure to salt-laden wind off the bay accelerates coating breakdown at edges and fasteners. Add Whatcom County's long stretch of driving rain and the shaded, damp conditions that keep moss and algae established on north- and west-facing walls for most of the year, and you have a climate that specifically targets the weak points of any wood-based product. Manufacturers of engineered wood siding are explicit in their installation guides about caulking, priming cut edges, flashing details, and minimum ground clearance — and for good reason. Skip one of those steps, or let caulk joints age past their service life without recaulking, and moisture intrusion becomes a matter of when, not if.
Maintenance Is the Real Cost Difference
The lower material price on engineered wood siding is real, but it doesn't account for what the product asks of the homeowner afterward. To get a normal service life out of it in this climate, you're looking at:
- Regular recaulking of joints, seams, and trim as sealant ages and shrinks
- Repainting on a shorter cycle than fiber cement, since the factory coating is the primary moisture barrier
- Prompt attention to any nick, gouge, or exposed cut edge before it becomes an entry point
- Active moss and algae control on shaded walls, since a compromised coating gives organic growth more to hold onto
None of that is unreasonable to ask of a building material — but it's ongoing work, and it's easy to fall behind on, especially on a rental, a second home, or a busy household. Fiber cement doesn't eliminate maintenance either, but it removes moisture intrusion as the thing that ends the siding's life, because the core material itself doesn't absorb and swell the way wood does.
Why We Standardized on James Hardie
James Hardie fiber cement is cement, sand, and cellulose fiber, cured into a dense, non-combustible board. It doesn't swell with moisture the way wood-based products do, and it holds paint and factory finish differently as a result. We install it with Hardie's ColorPlus factory-baked finish, which is engineered to resist fading and doesn't rely on the homeowner keeping up a repaint schedule to protect the substrate underneath. Hardie also makes climate-specific HZ product lines, and we use the version engineered for the wetter, harsher weather patterns typical of the Pacific Northwest rather than a generic national product.
Fiber cement is heavier and less forgiving to install than engineered wood — it demands correct fastening, clearances, and joint treatment just like any siding product — which is exactly why we treat installation as seriously as the material choice. Done right, it comes with a strong transferable warranty and a track record of holding up in coastal, high-moisture climates like ours for decades, not years.
Our Bottom Line
| Factor | Engineered Wood | James Hardie Fiber Cement |
|---|---|---|
| Core material behavior in moisture | Wood-based, can swell and degrade if compromised | Cement-based, doesn't absorb and swell |
| Finish durability | Factory primer, needs repainting on shorter cycle | ColorPlus factory finish, built for long-term color hold |
| Fire resistance | Combustible | Non-combustible |
| Upfront material cost | Generally lower | Generally higher |
| Maintenance in coastal PNW climate | Higher — caulk, paint, edge care | Lower — durable core and finish |
Engineered wood isn't a bad product everywhere, but for homes exposed to Semiahmoo's salt air, sustained rain, and moss-friendly shade, we don't think it's the right long-term investment, and we've chosen not to install it. If you're weighing your options for a siding project, we're happy to walk your home, talk through what we see, and give you a free, no-pressure estimate.