Lynden Siding Composite Decking for Aldergrove, BC Homeowners
Aldergrove sits just across the border from Lynden, close enough that many homeowners there already cross into Whatcom County for contractors, suppliers, and services that aren't worth the wait on the Canadian side. Decking is one of those jobs. A deck built in this part of the world — whether the address is in British Columbia or Washington State — deals with the same weather: long wet winters, driving rain that comes in sideways more often than straight down, a marine-influenced air that carries salt and moisture year-round, and a shoulder season where moss and algae get a serious head start on anything that holds water or shade. Composite decking done right handles all of that. Composite decking done wrong just hides the problem under a nicer-looking surface for a year or two before it shows up anyway.
This page is about that one job — composite decking — for that one area. Not a general overview of every decking material we've ever touched, but what actually matters if you're planning a composite deck for a home in or near Aldergrove.
What This Climate Does to a Deck Over Time
The Pacific Northwest border region isn't brutally cold, but it is relentlessly wet. That's a different kind of stress on a deck than a hot, dry climate puts on one. A few things happen here that don't happen the same way elsewhere:
- Moss and algae growth — shaded or north-facing sections of a deck can stay damp for days at a time during the fall and winter, which is exactly what moss and algae need to establish.
- Driving rain intrusion — wind-driven rain doesn't just fall on a deck, it pushes sideways into ledger connections, stair stringers, and any gap where flashing was skipped or done poorly.
- Salt-tinged air — proximity to the Salish Sea and Boundary Bay means fasteners, brackets, and any exposed metal hardware are under more corrosion pressure than in a purely inland climate.
- Freeze-thaw cycling — it doesn't get brutally cold here, but the occasional freeze after a soaking-wet stretch is enough to stress joints and fasteners that were installed with no room to move.
None of this means composite decking is a bad fit — it's actually one of the better materials for this exact climate. It means the installation has to account for all four of these things, not just the first one homeowners usually think about.
Composite vs. Wood vs. PVC — What Actually Holds Up Here
Every decking material has a real trade-off. We'd rather walk you through them honestly than push whatever's easiest for us to install.
| Material | How it handles this climate | Ongoing maintenance | Typical lifespan here |
|---|---|---|---|
| Pressure-treated wood | Absorbs moisture readily; prone to moss growth, splintering, and warping without regular upkeep | Annual cleaning, periodic sealing/staining | 10-15 years before major repair or replacement |
| Composite (capped) | Resists moisture absorption and moss adhesion far better than wood; surface doesn't splinter or gray unevenly | Periodic washing to keep the cap clear of algae film | 25-30+ years, manufacturer-dependent |
| PVC decking | Fully moisture-resistant but can look and feel less like natural wood; some products are more sensitive to installation temperature | Low, similar to composite | 25-30+ years |
We install composite as our standard recommendation for this area because it strikes the best balance: it doesn't feed moss and algae the way untreated or under-maintained wood does, it isn't as installation-sensitive as some PVC products in a cold, wet install season, and it comes with real manufacturer warranty structures that mean something. That's a professional judgment call based on trade-offs, not a claim that other materials are junk — plenty of wood decks last a long time when someone actually maintains them.
Board Style Matters Too
Within composite, there's a real difference between fully-capped boards (a protective polymer shell on all four sides) and boards capped on three sides or less. In a climate with this much sustained moisture exposure, the cut ends and any exposed core matter — that's where water gets in first if flashing and end-capping weren't handled correctly during install.
What a Correct Composite Deck Build Actually Involves
The board itself is maybe a third of what determines whether a composite deck holds up. The rest is substructure and detailing — the parts that don't show up in a photo but are exactly what fails first in a wet climate.
Substructure and Framing
Joist spacing has to match the specific composite product's engineering requirements — composite deflects differently than wood, and manufacturers publish minimum spans for a reason. We also grade the substructure for drainage so water isn't sitting under the deck surface after every rain.
Ledger Flashing
Where a deck attaches to the house is the single most common failure point on any deck in a wet climate, composite or not. Proper flashing — installed so water sheds away from the house wall, not into it — is non-negotiable, regardless of what decking material sits on top.
Fasteners and Hardware
Given the salt-tinged air in this region, we use corrosion-resistant fasteners and hidden fastener systems rated for coastal exposure. Cheap or mismatched hardware is one of the most common places we see early failure on decks that were otherwise built with good materials.
Ventilation and Clearance
Composite still needs airflow underneath. A deck built too close to grade, or without adequate under-deck ventilation, traps moisture regardless of what's on the surface — that trapped moisture is what eventually shows up as mold, odor, or substructure rot even when the composite boards themselves look fine.
Board Layout and Expansion Gaps
Composite expands and contracts with temperature more than most homeowners expect. Gaps between boards, around posts, and at the perimeter need to be sized correctly for the specific product — too tight, and you get buckling; too loose, and you get an uneven, unfinished look.
Our Process, Start to Finish
- On-site assessment — we look at the existing structure (if there is one), grading, sun/shade exposure, and how water currently moves around the area.
- Material selection — we walk through composite board options and finishes suited to the site, with honest input on what fits the budget and the exposure.
- Written estimate — a clear scope covering substructure work, flashing, fasteners, and finish decking, so there's no ambiguity about what's included.
- Permits and planning — decking projects often require a permit depending on height, attachment, and local jurisdiction; we handle this conversation up front rather than after the fact.
- Build — substructure first, then flashing and waterproofing details, then the composite surface, railings, and any stairs.
- Final walkthrough — we go over the finished deck together, including basic care so it looks the way it should for years, not just for the first season.
Cost Factors for a Composite Deck Project
Every deck is different, so we won't quote a number without seeing the site — but these are the variables that actually move the price:
| Factor | Why it matters |
|---|---|
| Deck size and shape | Square footage and the number of angles, cutouts, or level changes affect both material and labor |
| Substructure condition | New build vs. replacing/reinforcing an existing frame changes the scope significantly |
| Height and stairs | Elevated decks need railings, stringers, and often engineering review |
| Board tier | Composite lines range from entry-level to premium, with different colors, cap types, and warranty lengths |
| Site access | Backyard access, grading, and how far materials have to be carried affect labor time |
| Railings and fascia | Composite or aluminum railing systems and fascia boards add cost but also add to how the deck ages |
Maintenance: What Composite Actually Needs Around Here
Composite is genuinely low-maintenance compared to wood, but "low-maintenance" isn't "no-maintenance" — especially with a moss season this long.
- Rinse or lightly wash the deck a few times a year, more often in shaded areas, to keep algae film from establishing.
- Keep gutters and downspouts near the deck clear so water isn't dumping directly onto the surface or substructure.
- Sweep debris out of board gaps and off ledger areas before it composts in place through a wet winter.
- Check railing posts and stair connections annually for any movement — early looseness is easy to fix, ignored looseness isn't.
Why a Crew That Already Works This Area Matters
Aldergrove and Lynden share the same weather, but they don't automatically share the same permitting process, inspection requirements, or supplier lead times — and that's exactly the kind of detail that trips up a contractor who doesn't already work this specific border area regularly. A crew based in Lynden that's used to serving homeowners on both sides of the crossing already knows what documentation and site logistics look like for this stretch of Whatcom County and the surrounding area, instead of learning it for the first time on your project.
There's also a simple practical benefit: a local crew can actually get to the site for a real walkthrough, follow up quickly if a question comes up mid-build, and stand behind the work afterward because they're not driving in from somewhere far away for a one-time job.
What to Ask Before Hiring a Deck Contractor Here
- Do they specify fully-capped composite boards, or is that only offered as an upgrade?
- Will they detail ledger flashing in writing, not just verbally?
- What fastener system do they use, and is it rated for coastal/marine exposure?
- Who handles the permit application and inspection scheduling?
- What's the manufacturer's warranty on the specific board line being quoted, and who registers it?
If you're weighing a composite deck for a home in or near Aldergrove, we're happy to walk the site, talk through material options honestly, and put together a straightforward written estimate — no pressure, no upsell script. There's a short form below to get that conversation started.