Blaine Two Engineered Sidings, One Whatcom County Climate
If you're replacing siding in Blaine, two products keep coming up in estimates: James Hardie fiber cement and LP SmartSide. Both are a step up from vinyl in terms of durability and paintability, and both are marketed as engineered wood-alternative siding. But they're built from different materials, and those materials behave differently once they're facing salt air off Semiahmoo Bay, driving winter rain, and months of moss-friendly shade that Whatcom County is known for. We only install James Hardie, and we think homeowners deserve a straight explanation of why — not a sales pitch against the alternative.
What LP SmartSide Actually Is
LP SmartSide is an engineered wood product — strand fibers bonded with resin, treated with a zinc borate preservative, and coated with a resin-saturated overlay to resist moisture. It's a genuine improvement over old-style hardboard siding, which had a rough history with swelling and rot in wet climates. LP has addressed a lot of that with better treatment and factory coatings, and it installs fast, cuts easily, and costs less than fiber cement in most bids.
Where LP SmartSide Does Well
- Lighter weight, easier and faster to install than fiber cement
- Lower upfront material cost
- Holds paint reasonably well when factory-primed and installed correctly
- Wood-grain textures that read close to cedar
Where It Runs Into Trouble in a Marine Climate
SmartSide is still a wood-based product at its core. That means its long-term performance depends heavily on cut edges being sealed, caulking being maintained, and moisture never sitting against the board for extended periods. In a dry inland climate, that's manageable. In Blaine — with driving rain off the water, salt-laden air, and a shaded moss season that keeps north- and west-facing walls damp for weeks at a stretch — those maintenance margins get thin fast. Any gap in caulk, any field-cut edge that wasn't sealed, any spot where moss holds moisture against the surface becomes a place where the wood substrate can start to take on water. It's not a defect in the product; it's the nature of building a wood-based siding for a climate that doesn't dry out for months at a time.
What James Hardie Fiber Cement Is
James Hardie siding is made from cement, sand, and cellulose fiber — there's no wood substrate to absorb water in the first place. It's non-combustible, doesn't swell or delaminate from moisture exposure, and holds its shape and paint line over decades. Hardie's HZ5 product line is engineered specifically for climates with sustained damp conditions and freeze-thaw cycling, which describes most of Northwest Washington. The ColorPlus factory finish is baked on under controlled conditions, resists fading and chipping better than field-applied paint, and comes with a longer color warranty than most homeowners get from repainting a wood-based product every several years.
Where Fiber Cement Requires Respect
We won't pretend fiber cement is foolproof. It's heavier, requires proper fasteners and clearances, and needs correct flashing and caulking details just like any siding — installation quality matters as much as material choice. Cut edges need to be primed and sealed. But the underlying material itself doesn't rot, swell, or feed moss the way an organic substrate can, which removes one entire category of failure mode that we see repeatedly on wood-based sidings up here.
Side-by-Side
| Factor | LP SmartSide | James Hardie |
|---|---|---|
| Core material | Engineered wood strand | Fiber cement (no wood) |
| Moisture behavior | Resistant if sealed and maintained | Doesn't absorb or swell |
| Fire rating | Combustible | Non-combustible |
| Finish | Field or factory paint | Factory-baked ColorPlus finish |
| Upfront cost | Lower | Higher |
| Maintenance in a marine climate | Regular caulk/paint upkeep matters more | Lower long-term upkeep |
Why We Standardized on Hardie
We install exteriors for a living in Whatcom County, and we'd rather stand behind one product we trust in this climate than offer a cheaper option we know will demand more upkeep from the homeowner five or ten years down the line. LP SmartSide isn't a bad product — it's a reasonable choice in drier regions where maintenance schedules are easier to keep up with. But for a coastal town like Blaine, where salt air and prolonged dampness are just part of the deal, we've made non-combustible fiber cement our standard. It's less sensitive to the details that are hardest to keep perfect over decades: caulk lines, cut-edge sealing, and moss buildup against the wall.
If you're weighing siding options for a home in Blaine or elsewhere in Whatcom County, we're happy to walk your property, look at sun and moisture exposure on each side of the house, and give you a straightforward, no-pressure estimate for James Hardie siding done right.