Lynden Window Composite Decking Built for Kendall's Climate
Kendall sits inland in Whatcom County, in the same general stretch of the county as Lynden, without the direct spray a waterfront lot takes. That doesn't mean the weather goes easy on an outdoor deck here. This whole corner of Washington sits inside a marine-influenced system that pushes salt-tinged air well past the shoreline, and a deck built with no roof over it feels every bit of that exposure, along with driving rain that rarely falls straight down and a moss season that runs long and damp for most of the year. A deck is one of the more exposed structures on a property, sitting outside year-round in exactly the conditions that wear exterior work down fastest.
Composite decking has become the default choice for a lot of Kendall homeowners for good reason — it resists the moisture, staining, and organic growth that wood struggles with here. But "composite" covers a wide range of product quality, and the installation details underneath the boards matter just as much as which product you pick. This page covers what a Kendall composite deck actually needs from the material and the build, what a correct installation looks like, and how our process works for this specific part of Whatcom County.
What Kendall's Climate Does to a Deck
Salt Air and Fastener Corrosion
Even set back from open water, Kendall gets a steady dose of salt-carrying marine air moving through this part of the county. Salt accelerates corrosion in exposed metal — screws, brackets, post hardware, railing connectors — and a fastener that starts corroding loses holding strength well before it looks obviously bad. On a structure people walk, stand, and gather on, that's a real concern rather than a cosmetic one.
Driving Rain and Wind
Rain in this area is more often driven than vertical, pushed sideways by wind into railing posts, ledger connections, and the gaps between deck boards. A deck surface that would shed water fine on a calm day can still trap moisture the moment wind gets involved, and wind-driven rain is common enough here that a deck built assuming still, straight-down weather is being built for the wrong conditions.
A Moss Season That Runs Most of the Year
Mild temperatures and near-constant moisture give moss and mildew a long stretch of the year to work on any horizontal surface, and a deck holds water longer than a vertical wall does between rain events. Shaded decks and north-facing surfaces are usually the first to show it, and any decking material with real surface porosity gives moss something to grip onto and hold.
Why Composite Decking Fits This Climate
Composite decking exists specifically to resist the kind of sustained moisture exposure that wears wood down fastest, which is a large part of why it's become the common choice for decks in Kendall and across this part of Whatcom County. But not all composite is built the same way, and the gap in real-world performance between a well-made board and a cheaper one shows up faster here than it would in a drier climate.
Capped vs. Uncapped Composite
Capped composite boards have a plastic shell wrapped around a wood-fiber composite core, and that cap layer is what actually resists moisture absorption, staining, and UV fade. Uncapped composite, or boards capped on only some sides, still have exposed wood fiber somewhere on the board — usually at the cut ends — and that's where moisture works its way in over time. In a climate that stays damp for most of the year, the cap layer isn't a marketing upgrade, it's the difference between a board that needs occasional washing and one that slowly darkens and swells at the edges.
How Composite Compares to Wood and PVC
Wood, whether cedar or pressure-treated lumber, can look good when new but needs regular sealing or staining to hold up against sustained moisture here, and it's usually the first material on a property to show moss, graying, or soft spots if maintenance slips. Cellular PVC decking contains no wood fiber at all, so it resists moisture even better than capped composite in some respects, but it typically costs more and can flex more under heavy point loads. Composite sits in between on cost while matching or beating PVC on most of what actually matters for a deck in this climate — moisture resistance, moss resistance, and low upkeep.
| Material | Moisture & Salt-Air Resistance | Moss Resistance | Typical Upkeep |
|---|---|---|---|
| Capped composite | Strong — cap layer blocks moisture absorption and staining | Good on most product lines | Occasional washing |
| Uncapped composite | Moderate — exposed fiber at cuts and edges absorbs moisture | Fair; more prone to buildup over time | Periodic cleaning, more attention at cut ends |
| Cellular PVC | Excellent — no wood fiber to absorb moisture | Strong, smooth non-porous surface | Occasional washing |
| Cedar | Moderate — natural resistance, but needs sealing | Fair when sealed and maintained regularly | Regular oiling or sealing |
| Pressure-treated wood | Weak against sustained moisture exposure over time | Poor without regular treatment | Regular sealing or staining |
What a Correctly Installed Composite Deck Involves
The decking surface gets most of the attention when homeowners picture a new deck, but in Kendall's climate, what's underneath the boards is what actually determines how long the deck lasts. A composite deck built correctly for this area includes:
- Framing sized and rated for the span and load, using pressure-treated lumber suited to sustained moisture exposure
- Stainless steel or coastal-grade corrosion-resistant fasteners throughout, not standard hardware that starts corroding in salt-tinged air within a few seasons
- Hidden fastener systems on the deck surface where the specific composite product supports it, cutting down on exposed metal and giving a cleaner walking surface
- Correct board gapping for drainage and thermal movement, so wind-driven rain and everyday moisture can actually drain and dry between boards instead of sitting
- Proper ledger board flashing where the deck ties into the house — one of the most common places moisture gets into a poorly built deck
- Joist spacing matched to the specific composite product's span rating, since composite typically requires tighter joist spacing than wood decking of the same dimension
- Railing and post attachment sized appropriately for the site's wind exposure
- Grading and airflow underneath the deck so moisture doesn't sit trapped against the framing between storms
Skip any one of those and the deck usually still looks fine for the first year or two. Composite decking's whole selling point is that the surface resists wear — but a surface that resists wear sitting on framing and fasteners that don't just moves the failure point underneath, where it's harder to see and more expensive to fix.
Choosing the Right Composite Board for a Kendall Deck
Board Profile and Grip
Composite boards come with different surface textures, from smooth wood-grain finishes to deeper embossed patterns designed for slip resistance. Given how much of the year Kendall stays damp, a board with real texture underfoot is worth prioritizing over a smoother, more polished-looking profile, especially on stairs and any deck area that stays shaded through the day.
Color and Heat Considerations
Darker composite colors absorb more heat on the occasional sunny day, but they also tend to show water spotting and pollen less than lighter colors, which matters more here than the heat question does given how few genuinely hot days this area sees. Lighter and mid-tone colors can also make it easier to spot early moss growth on a shaded section before it spreads, which is a practical advantage as much as an aesthetic one.
Warranty Structure
Composite decking warranties vary widely — some cover structural integrity for decades but limit fade and stain coverage to a much shorter window, and the fine print on what voids coverage (certain cleaning products, certain fastener types) is worth actually reading before you commit to a product. We'll go over what a given manufacturer's warranty actually covers as part of picking a board, rather than treating the warranty length on the box as the whole story.
How Our Process Works
We start with a site visit to look at what's actually there — existing structure condition if it's a replacement, grading and drainage around the deck footprint, sun and wind exposure through the day, and how shaded the site stays given nearby trees or the house's own footprint. From there we go through composite product and color options that fit the budget and how the space will get used, whether that's a small deck off a kitchen or a larger one built for entertaining.
Permitting in Kendall follows Whatcom County's standard setback, structural, and elevation requirements, and we handle that as part of the job rather than leaving it for the homeowner to sort out. Once permitted, the build follows the sequence above — substructure and framing first, sized and fastened for the site's actual exposure, then the composite decking surface, railing, and any stairs or trim work. We finish with a walkthrough covering what your specific board actually needs going forward, which for most composite products is minimal, but not nothing.
Keeping a Composite Deck Looking Right in This Climate
Composite decking is low-maintenance compared to wood, but "low-maintenance" isn't the same as "no maintenance," especially with a moss season that runs most of the year. A short list worth keeping in mind:
- Rinse or wash the deck surface periodically to clear pollen, dirt, and organic buildup before it works into the cap layer or texture grooves
- Keep gaps between boards clear of leaves and debris so water and airflow can move through the way the design intends
- Sweep or brush shaded, north-facing sections more often, since that's where moss takes hold first
- Check railing posts and visible hardware once a year for early corrosion or loosening, especially heading into the wet season
- Trim back overhanging branches or plants that hold moisture against the deck or block sun and airflow across the surface
- Use cleaners the manufacturer actually recommends — some pressure-washing techniques or harsh chemical cleaners can void a composite warranty
Why Hiring a Crew That Already Works Kendall Matters
A crew that mostly builds decks in drier, more sheltered parts of the county can still put one together competently, but a Kendall job has variables that come up regularly here and less often elsewhere — corrosion-grade fastener requirements from sustained salt-tinged air, board gapping that actually accounts for how long surfaces stay damp, and moss pressure that runs longer here than it does in a lot of towns. Working this area regularly means we're not guessing at those requirements on your project. Lynden Window Co has seen which composite lines actually hold up against Kendall's specific combination of salt air, driving rain, and moss, and which fastener grades and framing details are worth the extra time rather than an unnecessary upsell.
That familiarity also shows up in smaller judgment calls — how to orient a deck for the sun and shade a particular lot actually gets, or being straightforward about what a composite deck here realistically needs to last versus what's just an extra line item.
Get a Straight Answer About Your Kendall Deck
Whether you're replacing an aging wood deck, building new, or want an honest read on what a composite deck would take on your Kendall property, we're glad to walk the site with you and lay out the options plainly. Reach out below for a free, no-pressure estimate.