Birch Bay Siding If you're re-siding a home in Birch Bay, two products will keep coming up in your research: James Hardie fiber cement and LP SmartSide engineered wood. Both are legitimate step-up products from vinyl, and both are backed by real manufacturers with real engineering behind them. But they are different materials with different failure modes, and in a place like Whatcom County — where salt air off the bay, driving winter rain, and a long moss season all work on a house year-round — those differences matter more than they would somewhere drier.
This page lays out how the two products actually compare, honestly, so you can understand why we install one of them and not the other.
What each product is made of
James Hardie siding is fiber cement: a mix of Portland cement, sand, and cellulose fiber, cured into a rigid, dense board. It is not wood, and it does not have wood's biology — it can't rot, and it doesn't feed mold or insects the way organic material does.
LP SmartSide is an engineered wood product: wood strands and fibers bonded with resins and treated with a zinc borate additive for insect and fungal resistance, then coated with a wax layer and primer. It's a real improvement over old-school primed spruce or cedar lap siding, and the treatment does add meaningful resistance to rot compared to untreated wood. But at its core, it's still wood fiber — an organic material — with a factory coating protecting it.
Why moisture behavior matters here
Birch Bay homes deal with moisture from two directions: wind-driven rain coming off the water, and long stretches of damp, low-sun weather that keep surfaces wet for days at a time. That combination is hard on any siding, but it's particularly unforgiving of any product where the core material is organic.
LP SmartSide's zinc borate treatment and factory coating are engineered to resist moisture intrusion, and the product performs well when installation is done exactly to spec — every cut edge sealed, every panel properly flashed, caulk joints maintained on schedule. The catch is that the wood substrate underneath is only as protected as that coating stays intact. Any breach — a missed field-cut seal, a fastener not set correctly, caulk that's cracked and gone unnoticed for a season — gives moisture a path into a material that can still swell, delaminate, or break down once wet. In a climate with this much cumulative rain exposure, that maintenance discipline has to hold up year after year, not just at installation.
Fiber cement doesn't remove maintenance from the equation entirely — caulk joints and paint film still need attention over time — but the core board itself isn't the thing failing. It's simply inert to the moisture problem in a way an organic substrate can't be.
Salt air and the coastal factor
Birch Bay's proximity to the water means airborne salt settles on every exterior surface, accelerating the breakdown of finishes and fasteners alike. This is a factor for any siding material — it argues strongly for high-quality fasteners and trim regardless of what's on the wall — but it raises the stakes on coating integrity specifically for engineered wood products, since a compromised finish here is being asked to hold up against both moisture and salt exposure at once.
Moss, algae, and the maintenance calendar
Anyone who's owned a home in this part of Washington knows the moss and algae season is long — shaded north walls and anything under tree cover can stay damp and green for months. Both products can develop surface growth; it's a function of the local environment, not the siding brand. The difference shows up in what that growth is sitting on. On fiber cement, moss and algae are a cosmetic issue you can wash off without worrying about what's happening underneath. On any wood-based product, prolonged surface moisture from moss and algae is one more thing keeping that surface — and by extension, the substrate under a compromised coating — wet for longer.
Fire performance and warranty structure
James Hardie fiber cement is non-combustible, which matters for insurance conversations and for peace of mind, especially as wildfire smoke and regional fire risk have become a bigger part of Pacific Northwest summers. LP SmartSide, being wood-based, does not carry that same non-combustible rating.
On warranty, James Hardie's ColorPlus factory-finish products carry a strong, transferable limited warranty covering both the substrate and the finish — a real benefit if you sell the home before the siding's useful life is up. LP's warranty is also substantial, but it's built around a wood-composite product, and warranty terms for wood-based siding typically carry more exclusions tied to installation and maintenance compliance than fiber cement warranties do.
Why we install Hardie and not LP SmartSide
We're not going to tell you LP SmartSide is a bad product — plenty of homes around western Washington have it, and when it's installed correctly and maintained on schedule, it performs. Our issue isn't with the manufacturer's engineering; it's with what we're willing to stand behind on a house that sits this close to the water and gets this much rain. We'd rather install a material that removes the organic-substrate variable entirely than install one that performs well only if every coating breach gets caught and repaired for the next 20-plus years.
That's why we standardized on James Hardie: non-combustible fiber cement, the HZ product lines engineered for wet climates, factory ColorPlus finishes that hold their color without the field-painting cycle, and a warranty structure that reflects real confidence in the product over the long term — all a better match for what a Birch Bay roofline actually has to survive.
If you're weighing siding options for a home in Birch Bay or anywhere in Whatcom County, we're happy to walk your property, look at your exposure to sun, wind, and moisture, and give you a straight answer on what makes sense. Reach out for a free, no-pressure estimate — there's no obligation, just an honest look at your home.