Lynden Siding Composite Decking Built for What Aldergrove Actually Deals With
Aldergrove sits just across the international line from Lynden, connected by the Aldergrove–Lynden border crossing that a lot of local families cross more casually than they'd cross town. The two communities share close to the same weather, the same building challenges, and often the same contractors, since a line on a map doesn't change what a Pacific Northwest winter does to an outdoor deck. Homes in Aldergrove deal with salt-tinged marine air moving in off the wider Salish Sea region, driving rain that comes in sideways more often than straight down, and a moss season that can run most of the year on shaded surfaces. A deck sits outside in all of it, with no roofline or wall to take the edge off.
Composite decking exists specifically to hold up better than wood in that kind of climate, but "composite" covers a wide range of quality and construction, and not every board performs the same way once it's been outside through a few wet seasons. This page covers what an Aldergrove deck actually needs from its material and construction, what a correct composite install involves, and what's worth knowing about building a deck for a property that sits right on this specific stretch of the border.
What This Corridor's Climate Does to a Deck
Salt-Tinged Marine Air
Even well inland from open saltwater, homes across this part of Whatcom County and the neighboring Fraser Valley pick up a steady dose of salt-influenced marine air moving through on the region's weather systems. That air accelerates corrosion in exposed metal — fasteners, 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 and stand on every day, that's a structural concern, not a cosmetic one.
Driving Rain That Doesn't Fall Straight Down
Storms moving through this corridor push rain sideways as often as they drop it straight down, driving moisture up under railings, into ledger connections, and between boards that aren't gapped correctly. A decking surface that would shed water fine on a calm day can trap it the moment wind gets involved, and around here wind-driven rain is closer to the rule than the exception through fall and winter.
A Moss Season That Runs Most of the Year
Mild temperatures and near-constant moisture give moss and mildew a long growing season on both sides of the border, and horizontal deck surfaces are usually among the first places it takes hold, since they hold water longer than a vertical wall and stay damp between rain events. Shaded decks and north-facing surfaces show it first, and any decking material with even a little surface porosity gives moss something to grip onto.
What "Composite Decking" Actually Means
Composite decking is generally a blend of wood fiber and plastic, but the ratio, the plastic type, and how the board is finished vary a lot between manufacturers and product lines. Two distinctions matter most for a climate like this one.
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 UV degradation. Uncapped composite, the older style of the product, is exposed on all sides, which means it can absorb moisture and is more prone to mold growth and surface wear over time. In a climate with this much sustained rain and humidity, that difference shows up faster than it would somewhere drier, which is why we default to capped composite on jobs in this area.
Where PVC Fits In
Some manufacturers also offer fully cellular PVC decking, with no wood fiber in it at all. PVC resists moisture absorption completely and some lines run cooler underfoot, but it can flex more than composite under heavy point loads and generally costs more. Which one makes sense for a given deck usually comes down to budget, how much shade the deck sits in, and how the space gets used, not a blanket rule that one always beats the other.
| Material | Handling Salt Air & Moisture | Moss Resistance | Upkeep |
|---|---|---|---|
| Capped composite | Strong — cap layer resists moisture and staining | Good on most lines | Occasional washing |
| 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 |
| Cedar | Moderate — natural resistance, but needs sealing | Fair when sealed and maintained | Regular oiling or sealing |
| Pressure-treated wood | Weak against sustained moisture exposure over time | Poor without regular treatment | Regular sealing or staining |
What a Correct Composite Deck Build Involves Here
The decking boards get most of the attention, but the framing, fasteners, and drainage underneath are what actually determine how long the deck lasts in this climate. A build done right for an Aldergrove home includes:
- Framing material suited to sustained moisture exposure — pressure-treated lumber rated for the application, sized correctly for the span and load
- 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 and giving a cleaner walking surface
- Correct board gapping for drainage and material movement, so wind-driven rain and standing moisture can actually drain and dry between boards
- Proper ledger board flashing where the deck ties into the house, since that connection point is one of the most common places moisture gets in on a poorly built deck
- Joist spacing matched to the specific decking product's span rating rather than a generic framing layout
- Ventilation and grading underneath the deck so moisture doesn't sit against the framing between storms
Skip any one of those and the deck usually still looks fine on day one. The problems show up a few winters later, as a soft joist, a loosening railing post, or fastener corrosion staining the boards around it.
Crossing the Line: What Changes, What Doesn't
Same Climate, Different Permitting Authority
The weather doesn't care where the border sits, but the paperwork does. A deck project on the Aldergrove side of the line falls under Township of Langley and British Columbia requirements rather than Whatcom County and Washington State rules, and the two systems aren't identical. We're upfront with Aldergrove homeowners about that difference rather than assuming the process works the same way it does on jobs a few miles south — if you're not sure what's required for your specific property, that's a conversation worth having early, before material or design decisions get locked in.
A Crew That Already Makes the Crossing
Working this corridor regularly means the drive across the border isn't a novelty for us, and neither is designing a deck for a property that sits close enough to the line that homeowners on both sides deal with the same weather, similar lot conditions, and often the same general contracting questions. That familiarity matters more than it might seem — it's the difference between a contractor treating your project as a one-off crossing and one who already knows this specific stretch of ground.
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, sun and shade patterns through the day, and how the property sits relative to prevailing wind and rain. From there we talk through decking material options that fit the budget and how the space will actually get used, whether that's a quiet spot off the kitchen or a larger deck built for entertaining.
Once material and design are settled, the build follows the sequence above: substructure and framing first, sized and fastened for the site's actual exposure, then the decking surface, railing, and any stairs or trim work. We finish with a walkthrough covering what your specific material actually needs going forward, which for most modern composite decking is minimal, but not nothing.
What Composite Decking Still Needs From You
Composite decking is low-maintenance compared to wood, not maintenance-free. A little routine care goes a long way toward getting the full life out of it in this climate:
- Rinse or wash the deck surface periodically to clear salt-influenced residue, pollen, and organic buildup before it works 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 hold moisture against the deck or block sun and airflow across the surface
- Address any soft framing or standing water underneath right away — that's a structural issue, not a cosmetic one, and it doesn't improve with time
Why It Matters That We Already Work Aldergrove
A crew that mostly builds decks further from the border can still install composite decking competently, but an Aldergrove job has a few variables that don't come up as often elsewhere: knowing which side of the line a given permitting question falls under, corrosion-grade fastener requirements from sustained marine-influenced air, and moss pressure that runs longer here than it does in drier parts of the region. Working this area regularly means we're not guessing at those requirements on your project. We've seen which composite lines actually hold up against this corridor's specific combination of salt-tinged air, driving rain, and moss, 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 wind and rain a particular lot actually sees, and being straightforward with Aldergrove homeowners about what a deck here realistically needs to last, on either side of the border.
Get a Straight Answer About Your Deck
Whether you're replacing a tired deck, building new, or want an honest read on what composite decking would take on your Aldergrove 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.