Lynden Siding Composite Decking Built for Kendall's Climate
Kendall homes sit in a stretch of Whatcom County that puts real wear on anything built to sit outside year-round, and a deck takes more of that punishment than almost any other structure on a property. Salt-tinged air off the water works steadily on exposed metal and fasteners. Wind-driven rain doesn't fall politely straight down here — it gets pushed sideways and up under railings and between boards that aren't gapped or drained correctly. And a long, damp moss season settles into shaded, north-facing deck surfaces and stays there for months at a stretch, longer than most homeowners expect. Composite decking is built specifically to hold up better against that combination than wood does, but "composite" covers a wide range of product quality, and the installation details underneath the boards matter just as much as the boards themselves.
This page covers what a composite deck actually needs to hold up on a Kendall property, what a correct installation involves given this area's weather, and how our process works from first site visit to final walkthrough.
What Kendall's Climate Does to a Deck
Salt Air and Fastener Corrosion
Salt-laden air moving through this part of Whatcom County doesn't announce itself the way a storm does, but it works continuously on any exposed metal — screws, brackets, post hardware, railing connectors. A fastener that starts corroding loses holding strength well before it looks obviously bad, and on a structure people walk and stand on every day, that's a real concern rather than a cosmetic one. It's also one of the easiest details for a rushed installer to get wrong, because standard-grade hardware often looks identical to coastal-grade hardware right up until it isn't.
Driving Rain, Not Straight-Down Rain
Rain in this region rarely falls in a way that's easy on a structure. Wind pushes it sideways into railings, up under fascia boards, and between deck boards that don't have the right gap for drainage and airflow. A deck that would shed water fine on a calm day can still trap moisture the moment wind gets involved, and around here, wind gets involved often. That's why drainage detailing at the board level and at the ledger connection to the house matters more in Kendall than it would in a drier, more sheltered climate.
A Moss Season That Runs Most of the Year
Mild temperatures combined with near-constant moisture give moss a long growing season in this part of the county, and a horizontal deck surface is one of the first places it takes hold — it holds water longer than a vertical wall and stays damp between rain events in a way siding never has to. Shaded decks and north-facing surfaces are usually first to show it, and any decking material with even a little surface porosity gives moss something to grip onto and spread from.
What "Composite Decking" Actually Means
Composite decking is generally a blend of wood fiber and plastic, but the ratio, plastic type, and finish vary significantly between manufacturers, and that variation is exactly where quality differences show up fastest in a wet, mossy climate.
Capped vs. Uncapped
Capped composite boards have a plastic shell wrapped around a wood-plastic composite core, which protects that core from moisture absorption, staining, and the kind of surface degradation that gives moss and mildew something to grab onto. Uncapped composite is the older style of the product, with the wood-plastic blend exposed on all sides, so it absorbs more moisture and is more prone to fading and mold growth over time. In a climate that stays damp for months at a stretch, that difference between capped and uncapped shows up years sooner than it would somewhere drier, which is why we standardize on capped composite for decks in this area.
Composite vs. Cellular PVC
Some manufacturers also make fully cellular PVC decking, which contains no wood fiber at all. PVC resists moisture absorption completely, which can matter on a heavily shaded, slow-to-dry lot, but it can flex more under heavy point loads and typically costs more than composite. We'll walk through whether capped composite or PVC fits a given deck better based on sun exposure, shade, and budget — there isn't one right answer for every yard in Kendall.
What a Correct Composite Deck Build Involves Here
The decking boards get most of a homeowner's attention, but the framing, fasteners, and drainage details underneath are what actually determine whether the deck holds up through repeated wet seasons. A build done right for this climate includes:
- Framing material rated for sustained moisture exposure — pressure-treated lumber sized correctly for the span and load, not just whatever's cheapest at the yard
- Stainless steel or coastal-grade corrosion-resistant fasteners throughout, not standard hardware that starts corroding within a few wet seasons
- Hidden fastener systems on the deck surface where the product allows, reducing exposed metal on the walking surface and giving a cleaner finished look
- Correct board gapping for drainage and material movement, so wind-driven rain and standing moisture actually drain and dry between boards instead of sitting
- Proper ledger board flashing where the deck ties into the house, since that connection point is one of the most common places moisture works its way in on a poorly built deck
- Joist spacing matched to the specific composite product's span rating rather than a generic wood-framing layout
- Railing and post attachment sized appropriately for wind exposure, especially on elevated decks or more open lots
- Ventilation and grading underneath the deck so moisture doesn't sit against the framing between rain events
Skip any one of those and the deck usually still looks fine the first summer. The problems show up a couple of wet seasons later — a soft joist, a railing post that's started to loosen, or fastener corrosion staining the boards around it.
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, drainage and grade around the deck area, how much sun and shade the space gets through the day, and how exposed the lot is to wind and moisture. From there we talk through composite product options that fit the budget and how the space will actually be used, whether that's a quiet spot off the back door or a larger deck built for entertaining.
Permitting for deck work in Kendall generally 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 surface, railing, and any stairs or trim. We finish with a walkthrough covering what the specific product you chose actually needs going forward, which for most modern composite is minimal, but not nothing.
Composite Decking Compared to the Alternatives
| Material | Handling Salt Air & Moisture | Moss Resistance | Upkeep |
|---|---|---|---|
| Capped composite | Strong — cap layer resists moisture and staining | Good on most lines | Occasional washing; no sealing or staining |
| Cellular PVC | Excellent — no wood fiber to absorb moisture | Strong, smooth non-porous surface | Occasional washing |
| Uncapped composite | Moderate — some moisture absorption at exposed fiber | Fair; more prone to buildup over time | Periodic cleaning to manage mold and staining |
| Cedar | Moderate — natural resistance, but needs sealing | Fair when sealed and maintained | Regular oiling or sealing |
| Pressure-treated wood | Weak against sustained moisture and salt exposure over time | Poor without regular treatment | Regular sealing or staining |
What Composite Decking Still Needs From You
Composite decking is low-maintenance compared to wood, not maintenance-free, especially in a climate that stays damp as much of the year as this one does:
- Rinse or wash the deck surface periodically to clear pollen, organic buildup, and moss spores before they settle into the cap layer
- Keep gaps between boards clear of leaves and debris so water and airflow can move through the way the design intends
- Check railing posts and hardware once a year for early corrosion or loosening, especially heading into the wet season
- Trim back overhanging branches or plants that shade the deck or hold moisture against its edges
- Address any soft framing or standing water underneath right away — that's a structural issue, not a cosmetic one, and it doesn't improve on its own
Why It Matters That We Already Work Kendall
A crew that mostly builds decks elsewhere in Whatcom County can still put a composite deck together competently, but a Kendall job has the same combination of pressures that shapes every exterior project in this part of the county — sustained salt exposure, wind-driven rain that finds its way into places straight-down rain never would, and a moss season long enough to expose any shortcuts in drainage or gapping within a couple of years. Working this area regularly, based out of Lynden, means we're not guessing at those requirements on your project. We know which composite lines actually hold up against this specific combination of weather over years, not just the first dry summer, and which fastener grades and framing details are worth the extra time rather than an upsell.
That familiarity also shows up in the smaller judgment calls — how to orient a deck for the sun and shade a particular lot actually gets, and being straightforward with you about what a deck here realistically needs to last versus what's just an extra line item.
Get a Straight Answer About Your Deck
Whether you're replacing a tired wood deck, building new, or just want an honest read on what composite decking would take on your Kendall property, we're happy to walk the site with you and lay out the options plainly. Reach out below for a free, no-pressure estimate.